83.040.10 (Latex and raw rubber) 标准查询与下载

ASTM D6204-05 橡胶的标准试验方法.用非转动剪切流变仪测量未硫化橡胶的流变性能

1.1 This test method covers the use of a rotorless oscillating shear rheometer for the measurement of the flow properties of raw rubber and unvulcanized rubber compounds. These flow properties are related to factory processing.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Method for Rubber8212;Measurement of Unvulcanized Rheological Properties Using Rotorless Shear Rheometers

ASTM D2702-04 橡胶加工用化学药液的红外线吸收特性测定的标准实施规程

1.1 This analytical technique provides a simple, rapid practice to prove the identity of a rubber chemical before incorporation into a rubber mix by comparison of its infrared absorption spectrum with that of a reference specimen. 1.2 This technique can also be used to detect gross contamination or large differences in rubber chemicals. Thus, it can provide a basis for producer-consumer agreement. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Practice for Rubber Chemicals-Determination of Infrared Absorption Characteristics

ASTM D6204-04 橡胶的标准试验方法.用非转动剪切流变仪测量未硫化橡胶的流变性能

1.1 This test method covers the use of a rotorless oscillating shear rheometer for the measurement of the flow properties of raw rubber and unvulcanized rubber compounds. These flow properties are related to factory processing.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Method for Rubber8212;Measurement of Unvulcanized Rheological Properties Using Rotorless Shear Rheometers

ASTM D1417-03a 合成橡胶胶乳的标准试验方法

1.1 These test methods cover test procedures for synthetic rubber latices ABR, BR, CR, IIR, IR, NBR, NCR, NIR, PBR, PSBR, SBR, SCR, SIR, synthetic rubber latices having substitute carboxylic acid (COOH) groups on the polymer chain (X), and synthetic rubber latices that are reinforced (Y). Exceptions to the above are noted in the individual test procedures. The test methods include procedures for sampling, and for determining total solids, volatile unsaturates (residual styrene), pH value, surface tension, viscosity, coagulum, bound styrene, Mooney viscosity, mechanical stability, polystyrene reinforcement in contained polymer, and residual acrylonitrile content. Note 18212;The nomenclature used in these test methods is in accordance with Practice D 1418.1.2 The values stated in SI units are to be regarded as standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Methods for Rubber Latices-Synthetic

ASTM D6049-03 橡胶特性的标准试验方法.用平行板之间压力测定橡胶化合物和非硫化生橡胶黏性和弹性

The viscous and elastic behavior of unvulcanized rubbers and rubber compounds is of paramount importance in rubber manufacturing, since it affects processing, such as mixing, calendering, extrusion, and molding. The uniformity of these properties is equally important, as fluctuations will cause upsets in manufacturing processes. A test capable of measuring viscosity and elasticity of unvulcanized rubbers and rubber compounds, including their uniformity and prediction of processing behavior, is therefore highly desirable (see Practice D 6048 for further information). Compared to many other rheological tests, this test method measures viscosity and elasticity related parameters under conditions of low shear and has a high discriminating power. It can detect small rheological differences. A full discussion of the principles behind stress relaxation testing is given in Practice D 6048. Test results of this test method may be useful in predicting processability, but correlation with actual manufacturing processes must be established in each individual case, since conditions vary too widely. This test method is suitable for specification compliance testing, quality control, referee purposes, and research and development work.1.1 This test method is an adaptation of the German Standard DIN 53514, a further development of the former "Defo Test" (see Appendix X1).1.2 This test method is capable of measuring and characterizing the rheological behavior (viscosity and elasticity) of unvulcanized raw rubbers and rubber compounds, relating to the macro structure of rubber polymers (average molecular weight, molecular weight distribution, long chain branching, and micro- and macro-gel).1.3 The viscosity and elasticity of unvulcanized rubbers and rubber compounds are determined by subjecting cylindrical test pieces to a compression/recovery cycle. The dependency on shear rate at constant shear stress is evaluated and the material fatigue behavior is determined in repeat cycle testing.1.4 The non-Newtonian viscous and elastic behavior of rubbers and rubber compounds can also be evaluated.1.5 Statistical evaluation of the test data provides an indication of data variation, which may be employed as an estimate of the homogeneity of the material tested.1.6 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Method for Rubber Property8212;Measurement of the Viscous and Elastic Behavior of Unvulcanized Raw Rubbers and Rubber Compounds by Compression Between Parallel Plates

ASTM D6049-03(2013) 通过平行板之间压缩测量未硫化生橡胶和橡胶化合物粘性和弹性的橡胶性能的标准试验方法

5.1 The viscous and elastic behavior of unvulcanized rubbers and rubber compounds is of paramount importance in rubber manufacturing, since it affects processing, such as mixing, calendering, extrusion, and molding. The uniformity of these properties is equally important, as fluctuations will cause upsets in manufacturing processes. 5.2 A test capable of measuring viscosity and elasticity of unvulcanized rubbers and rubber compounds, including their uniformity and prediction of processing behavior, is therefore highly desirable (see Practice D6048 for further information). 5.3 Compared to many other rheological tests, this test method measures viscosity and elasticity related parameters under conditions of low shear and has a high discriminating power. It can detect small rheological differences. A full discussion of the principles behind stress relaxation testing is given in Practice D6048. 5.4 Test results of this test method may be useful in predicting processability, but correlation with actual manufacturing processes must be established in each individual case, since conditions vary too widely. 5.5 This test method is suitable for specification compliance testing, quality control, referee purposes, and research and development work. 1.1 This test method is an adaptation of the German Standard DIN 53514, a further development of the former “Defo Test” (see Appendix X1). 1.2 This test method is capable of measuring and characterizing the rheological behavior (viscosity and elasticity) of unvulcanized raw rubbers and rubber compounds, relating to the macro structure of rubber polymers (average molecular weight, molecular weight distribution, long chain branching, and micro- and macro-gel). 1.3 The viscosity and elasticity of unvulcanized rubbers and rubber compounds are determined by subjecting cylindrical test pieces to a compression/recovery cycle. The dependency on shear rate at constant shear stress is evaluated and the material fatigue behavior is determined in repeat cycle testing. 1.4 The non-Newtonian viscous and elastic behavior of rubbers and rubber compounds can also be evaluated. 1.5 Statistical evaluation of the test data provides an indication of data variation, which may be employed as an estimate of the homogeneity of the material tested. 1.6 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Method for Rubber Propertymdash;Measurement of the Viscous and Elastic Behavior of Unvulcanized Raw Rubbers and Rubber Compounds by Compression Between Parallel Plates

ASTM D1417-03 合成橡胶胶乳的标准试验方法

1.1 These test methods cover test procedures for synthetic rubber latices ABR, BR, CR, IIR, IR, NBR, NCR, NIR, PBR, PSBR, SBR, SCR, SIR, synthetic rubber latices having substitute carboxylic acid (COOH) groups on the polymer chain (X), and synthetic rubber latices that are reinforced (Y). Exceptions to the above are noted in the individual test procedures. The test methods include procedures for sampling, and for determining total solids, volatile unsaturates (residual styrene), pH value, surface tension, viscosity, coagulum, bound styrene, Mooney viscosity, mechanical stability, polystyrene reinforcement in contained polymer, and residual acrylonitrile content. Note 18212;The nomenclature used in these test methods is in accordance with Practice D 1418.1.2 The values stated in SI units are to be regarded as standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Methods for Rubber Latices-Synthetic

ASTM D1076-02 橡胶.浓缩的、氨储存的、乳状的和离心处理的天然胶乳的标准规范

1.1 This specification covers requirements for first grade concentrated natural rubber latex (see Table 1) of the following types:Type 1-Centrifuged natural latex preserved with ammonia only or by formaldehyde followed by ammonia.Type 2-Creamed natural latex preserved with ammonia only or by formaldehyde followed by ammonia.Type 3-Centrifuged natural latex preserved with low ammonia with other necessary preservatives.1.2 This specification is not necessarily applicable to latices prepared or preserved by other methods, and shall not be construed as limiting the desirability or usefulness of other types of latices. It does not apply to natural latex sources other than Hevea braziliensisnor to compounded latex concentrates.1.3 The analytical procedures applicable to the specifications are included and appear in the following order:SectionSampling6 and 7Total Solids8Dry Rubber Content9Total Alkalinity10Viscosity11Sludge Content12Coagulum Content13KOH Number14pH15Mechanical Stability16Copper and Manganese17Density18-30Volatile Fatty Acids31-35Boric Acid36Dry Films37Precision for All Test Methods381.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

Standard Specification for Rubber-Concentrated, Ammonia Preserved, Creamed, and Centrifuged Natural Latex

ASTM D4747-02(2008) 用气液色谱法测定乳胶中未反应单体含量的标准试验方法

Excessive amounts of unreacted monomer may cause concerns relating to toxicity and odor. This test method is designed to measure the unreacted monomer content of latexes. The results may be used to monitor the extent of polymerization during manufacture, as well as to establish maximum unreacted monomer content for regulatory purposes.1.1 This test method covers the determination of free monomer content of acrylic latexes. Monomers that have been successfully determined by this procedure include n-butyl methacrylate, n-butyl acrylate, styrene, and methyl methacrylate. The determination of other monomers has not been evaluated, but this test method is believed to be applicable. The established working range of this test method is from 100 to 1000 μg/g, but there is no reason to believe it will not work outside of this range, provided that appropriate dilutions and adjustments in specimen size are made. 1.2 The volatile composition of acrylic latexes is expected to change with time and environmental factors. This time dependence of the determination may be seen as an artificially large deviation of results, making the method mostly applicable for in-house quality control, where sampling and analysis conditions can be better controlled. 1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 7 for specific hazard statements.

Standard Test Method for Determining Unreacted Monomer Content of Latexes Using Gas-Liquid Chromatography

ASTM D4747-02 用气液色谱法测定乳胶中未反应单体含量的标准试验方法

Excessive amounts of unreacted monomer may cause concerns relating to toxicity and odor. This test method is designed to measure the unreacted monomer content of latexes. The results may be used to monitor the extent of polymerization during manufacture, as well as to establish maximum unreacted monomer content for regulatory purposes.1.1 This test method covers the determination of free monomer content of acrylic latexes. Monomers that have been successfully determined by this procedure include n-butyl methacrylate, n-butyl acrylate, styrene, and methyl methacrylate. The determination of other monomers has not been evaluated, but this test method is believed to be applicable. The established working range of this test method is from 100 to 1000 956;g/g, but there is no reason to believe it will not work outside of this range, provided that appropriate dilutions and adjustments in specimen size are made.1.2 The volatile composition of acrylic latexes is expected to change with time and environmental factors. This time dependence of the determination may be seen as an artificially large deviation of results, making the method mostly applicable for in-house quality control, where sampling and analysis conditions can be better controlled.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 7 for specific hazard statements.

Standard Test Method for Determining Unreacted Monomer Content of Latexes Using Gas-Liquid Chromatography

ASTM D4747-02(2014) 用气液色谱法测定乳胶中未反应单体含量的标准试验方法

4.1 Excessive amounts of unreacted monomer may cause concerns relating to toxicity and odor. This test method is designed to measure the unreacted monomer content of latexes. The results may be used to monitor the extent of polymerization during manufacture, as well as to establish maximum unreacted monomer content for regulatory purposes. 1.1 This test method covers the determination of free monomer content of acrylic latexes. Monomers that have been successfully determined by this procedure include n-butyl methacrylate, n-butyl acrylate, styrene, and methyl methacrylate. The determination of other monomers has not been evaluated, but this test method is believed to be applicable. The established working range of this test method is from 100 to 1000 μg/g, but there is no reason to believe it will not work outside of this range, provided that appropriate dilutions and adjustments in specimen size are made. 1.2 The volatile composition of acrylic latexes is expected to change with time and environmental factors. This time dependence of the determination may be seen as an artificially large deviation of results, making the method mostly applicable for in-house quality control, where sampling and analysis conditions can be better controlled. 1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 7 for specific hazard statements.

Standard Test Method for Determining Unreacted Monomer Content of Latexes Using Gas-Liquid Chromatography

ASTM D6048-02 生橡胶、非硫化橡胶和热塑弹性物的应力释放试验用标准实施规程

1.1 This practice covers several different techniques for determining the stress relaxation characteristics of rubber and rubberlike materials and for the possible interconversion of this stress relaxation information into dynamic mechanical properties.1.2 The techniques are intended for materials having stress relaxation moduli in the range of 103 to 108 Pa (0.1 to 1.5 x 104 psi) and for test temperatures from 23 to 225176;C (73 to 437176;F). Not all measuring apparatus may be able to accommodate the entire ranges. These techniques are also intended for measurement of materials in their rubbery or molten states, or both.1.3 Differences in results will be found among the techniques. Because of these differences, the test report needs to include the technique and the conditions of the test. This information will allow for resolving any issues pertaining to the test measurements.1.4 The generalized descriptions of apparatus are based on the measurement of force as a function of time. Mathematical treatment of that relationship produces information that can be representative of material properties. Mathematical transformation of the force measurements will first yield stress relaxation moduli with subsequent transformation producing dynamic mechanical properties.1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Practice for Stress Relaxation Testing of Raw Rubber, Unvulcanized Rubber Compounds, and Thermoplastic Elastomers

ASTM D6204-01 橡胶的标准试验方法.用非转动剪切流变仪测量未硫化橡胶的流变性能

1.1 This test method covers the use of a rotorless oscillating shear rheometer for the measurement of the flow properties of raw rubber and unvulcanized rubber compounds. These flow properties are related to facory processing. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Method for Rubber8212;Measurement of Unvulcanized Rheological Properties Using Rotorless Shear Rheometers

ASTM C1241-00(2005) 凝固过程中胶乳密封剂体积收缩的标准试验方法

Shrinkage of a sealant, after application in a building joint, is caused by loss of volatile components from the sealant. This loss results in a decrease in volume and, hence, a change in the sealantrsquo;shape. This change in shape, in some applications, should be taken into consideration for acceptable joint appearance and geometry. The shrinkage value obtained by this test method helps predict the appearance and geometry of the cured sealant in a building joint and is helpful in determining the amount and type of tooling to be done during installation of the sealant. Latex sealants cure primarily through water evaporation. They may also contain small amounts of other volatile components. However, in this test method all volatiles are treated as water. This assumption still provides a meaningful shrinkage value since the small quantities of other volatiles and their differences in density from that of water do not significantly affect the usefulness of the result obtained.1.1 This test method covers a laboratory procedure for determining volume shrinkage, which occurs during cure, of a latex sealant.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only.This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.Note 1A related ISO standard is ISO 10563. The user should compare to determine how it differs from this test method.

Standard Test Method for Volume Shrinkage of Latex Sealants During Cure

ASTM D5712-99 天然橡胶及其产品中蛋白质分析的标准试验方法

1.1 This test method provides an analytical test for determining the amount of total water extractable protein associated with natural rubber (NR) and its products. The test method involves an extraction and precipitation procedure followed by an assay of protein content. 1.2 For the purpose of this test method, the range of protein will be measured in terms of microgram to milligram quantities. 1.3 The test method is designed to be accurate and compatible with the industrial environment. 1.4 Steps are included in this test method to minimize the effects of interfering substances. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 9.

Standard Test Method for the Analysis of Aqueous Extractable Protein in Natural Rubber and Its Products Using the Modified Lowry Method

ASTM D6204-99 橡胶的标准试验方法.用非转动剪切流变仪测量未硫化橡胶的流变性能

1.1 This test method covers the use of a rotorless oscillating shear rheometer for the measurement of the flow properties of raw rubber and unvulcanized rubber compounds. These flow properties are related to facory processing. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Standard Test Method for Rubber8212;Measurement of Unvulcanized Rheological Properties Using Rotorless Shear Rheometers

ASTM D3194-99 天然橡胶塑性保持指数(PRI)的试验

1.1 This test method gives an indication of the oxidation resistance of raw natural rubber at a specified temperature. This resistance is indicated by the Plasticity Retention Index (PRI), a ratio expressed as a percentage of the aged plasticity to the original plasticity determined by means of a parallel plate plastimeter. A low PRI value indicates a poor resistance to oxidation. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use .

Standard Test Method for Rubber From Natural Sources-Plasticity Retention Index (PRI)

ASTM D6342-98(2003) 聚氨基甲酸乙酯原料的标准实施规范:利用近红外谱法测定多元醇中的羟基值

General Utility: 5.1.1 It is necessary to know the hydroxyl number of polyols in order to formulate polyurethane systems. 5.1.2 This practice is suitable for research, quality control, specification testing, and process control. Limitations: 5.2.1 Factors affecting the NIR spectra of the analyte polyols need to be determined before a calibration procedure is started. Chemical structure, interferences, any nonlinearities, the effect of temperature, and the interaction of the analyte with other sample components such as catalyst, water and other polyols needs to be understood in order to properly select samples that will model those effects which can not be adequately controlled. 5.2.2 Calibrations are generally considered valid only for the specific NIR instrument used to generate the calibration. Using different instruments (even when made by the same manufacturer) for calibration and analysis can seriously affect the accuracy and precision of the measured hydroxyl number. Procedures used for transferring calibrations between instruments are problematic and should be utilized with caution following the guidelines in Section 16. These procedures generally require a completely new validation and statistical analysis of errors on the new instrument. 5.2.3 The analytical results are statistically valid only for the range of hydroxyl numbers used in the calibration. Extrapolation to lower or higher hydroxyl values can increase the errors and degrade precision. Likewise, the analytical results are only valid for the same chemical composition as used for the calibration set. A significant change in composition or contaminants can also affect the results. Outlier detection, as discussed in Practices E 1655, is a tool that can be used to detect the possibility of problems such as those mentioned above.1.1 This standard covers a practice for the determination of hydroxyl numbers of polyols using NIR spectroscopy. 1.2 Definitions, terms, and calibration techniques are described. Procedures for selecting samples, and collecting and treating data for developing NIR calibrations are outlined. Criteria for building, evaluating, and validating the NIR calibration model are also described. Finally, the procedure for sample handling, data gathering and evaluation are described. 1.3 The implemenation of this standard requires that the NIR spectrometer has been installed in compliance with the manufacturer's specifications. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note 1-There is no equivalent or similar ISO standard.

Standard Practice for Polyurethane Raw Materials: Determining Hydroxyl Number of Polyols by Near Infrared (NIR) Spectroscopy

ASTM D6342-98 聚氨基甲酸乙酯原料的标准实施规范:利用近红外谱法测定多元醇中的羟基值

1.1 This standard covers a practice for the determination of hydroxyl numbers of polyols using NIR spectroscopy. 1.2 Definitions, terms, and calibration techniques are described. Procedures for selecting samples, and collecting and treating data for developing NIR calibrations are outlined. Criteria for building, evaluating, and validating the NIR calibration model are also described. Finally, the procedure for sample handling, data gathering and evaluation are described. 1.3 The implemenation of this standard requires that the NIR spectrometer has been installed in compliance with the manufacturer's specifications. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note 1-There is no equivalent or similar ISO standard.

Standard Practice for Polyurethane Raw Materials: Determining Hydroxyl Number of Polyols by Near Infrared (NIR) Spectroscopy

ASTM D1076-97 橡胶.浓缩的、氨储存的、乳状的和离心处理的天然胶乳的标准规范

1.1 This specification covers requirements for first grade concentrated natural rubber latex (see Table 1) of the following types: Type 1-Centrifuged natural latex preserved with ammonia only or by formaldehyde followed by ammonia. Type 2 -Creamed natural latex preserved with ammonia only or by formaldehyde followed by ammonia. Type 3 -Centrifuged natural latex preserved with low ammonia with other necessary preservatives. 1.2 This specification is not necessarily applicable to latices prepared or preserved by other methods, and shall not be construed as limiting the desirability or usefulness of other types of latices. It does not apply to natural latex sources other than Hevea braziliensis nor to compounded latex concentrates. 1.3 The analytical procedures applicable to the specifications are included and appear in the following order: Sampling, Total Solids, Dry Rubber Content; Total Alkalinity, Viscosity, Sludge Content, Coagulum Content, KOH Number, pH, Mechanical Stability, Copper and Manganese, Density, Volatile Fatty Acids, Boric Acid, Dry Films, Precision for All Test Methods. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

Standard Specification for Rubber-Concentrated, Ammonia Preserved, Creamed, and Centrifuged Natural Latex