Compositions with reduced aldehyde emissions
阅读说明：本技术 具有减少的醛排放的组合物 (Compositions with reduced aldehyde emissions ) 是由 武鹏飞 L.博纳米 张悦凡 J.K.P.博斯曼 朱雪荣 I.维尔瓦尔特 于 2018-12-13 设计创作，主要内容包括：本发明大体上提供用于制造具有减少的醛排放的聚氨酯泡沫的组合物,更尤其涉及可用于交通工具,如汽车内饰部件的组合物,其中所述组合物包含：(a)多官能异氰酸酯；(b)异氰酸酯反应性组合物；和(c)式(I)或(II)的化合物,其中化合物(c)以基于组合物的总重量计大约0.001至大约10,优选大约0.01至大约5,更优选大约0.05至大约2重量%的量存在于所述组合物中。所述组合物可减少PU泡沫中的醛排放,尤其是乙醛排放,并对泡沫的机械性质没有明显影响。(The present invention generally provides compositions for making polyurethane foams with reduced aldehyde emissions, and more particularly to compositions useful in vehicles, such as automotive interior parts, wherein the composition comprises: (a) a polyfunctional isocyanate; (b) an isocyanate-reactive composition; and (c) a compound of formula (I) or (II), wherein compound (c) is present in the composition in an amount of from about 0.001 to about 10, preferably from about 0.01 to about 5, more preferably from about 0.05 to about 2 weight percent, based on the total weight of the composition. The composition can reduce aldehyde emissions, especially acetaldehyde emissions, in PU foams without significantly affecting the mechanical properties of the foam.)
1. A composition for making a polyurethane foam, the composition comprising at least:
(a) a polyfunctional isocyanate;
(b) an isocyanate-reactive composition; and
(c) a compound of the formula:
wherein
R1 is selected from hydrogen, hydroxy or unsubstituted or substituted C1-C35Alkyl radical, C2-C35Alkenyl, aryl, alkylaryl or C1-C35An alkoxy group,
r2 is selected from a bond or unsubstituted or substituted aryl, C2-C35Alkenyl, alkylaryl, C1-C35Alkoxy or C1-C35An alkyl group, a carboxyl group,
a is an ion having a positive charge,
wherein compound (c) is present in the composition in an amount of about 0.001 to about 10, preferably about 0.01 to about 5, more preferably about 0.05 to about 2 weight percent, based on the total weight of the composition.
2. The composition of claim 1, wherein the NCO index of the composition is in the range of about 0.6 to about 1.5, preferably about 0.8 to about 1.3.
3. The composition of claim 1, wherein the NCO index of the composition is in the range of about 1.05 to about 10, preferably about 1.05 to about 4.
4. The composition of claim 1 wherein the polyfunctional isocyanate is selected from the group consisting of polymeric diphenylmethane diisocyanates, diphenylmethane diisocyanate isomer mixtures, or mixtures thereof.
5. The composition of claim 1, wherein the isocyanate reactive composition is a multifunctional polyol or a multifunctional amine, preferably a multifunctional polyol, more preferably a polyether polyol.
6. The composition of claim 1 where R1 is selected from the group consisting of hydrogen, hydroxy, and unsubstituted or substituted C1-C17Alkyl radical, C2-C35Alkenyl or aryl.
7. The composition of claim 1 where R2 is unsubstituted or substituted aryl, C2-C35Alkenyl or alkylaryl, preferably unsubstituted or substituted aryl or C2-C35Alkenyl, more preferably unsubstituted or substituted phenylene or naphthylene.
8. The composition of claim 1, wherein a is an alkali metal cation, an alkaline earth metal cation, a transition metal cation, ammonium, or hydrogen ion.
9. The composition of any one of claims 1 to 8, wherein the composition further comprises at least one catalyst.
10. The composition of claim 9, wherein the catalyst comprises an amine catalyst.
11. The composition of any one of claims 1 to 10, wherein the composition further comprises at least one blowing agent.
12. The composition of any one of claims 1 to 11, wherein the composition further comprises at least one chain extender.
13. A process for preparing a foam according to any one of claims 1 to 12, which comprises mixing at least components (a), (b) and (c) to form a mixture, and adding the mixture to component (a).
14. A process for preparing a foam according to any one of claims 1 to 12, which comprises mixing at least components (b) and (c) to form a mixture, and adding the mixture to component (a).
15. A method of forming an interior part of a vehicle using the composition of any one of claims 1 to 12.
Technical Field
The present invention relates generally to compositions having reduced aldehyde emissions, and more particularly to compositions useful in vehicle, such as automotive interior parts.
Background information
The emission of formaldehyde and acetaldehyde can cause unpleasant odors and health related problems. Methods of reducing formaldehyde emissions in polyurethane or Polyurea (PU) compositions using scavenger additives are known in the art. However, the known solutions do not provide compositions for the production of PU foams that can significantly reduce acetaldehyde emissions and still maintain satisfactory mechanical properties for further processing. Therefore, it is desirable to develop a composition suitable for producing PU foam that solves this problem.
In the prior art, US 20060141236 discloses the use of hydrazine compounds as aldehyde scavengers in polyurethanes. The viscosity of the composition is very high.
JP2005124743 discloses the use of an aldehyde scavenger (nitrogen containing organic compound) to reduce aldehyde volatile compounds in PU foam pads. However, the aldehyde scavengers used in this prior art are different from the present invention.
EP1428847 discloses an aldehyde scavenger. But it requires additional post-processing steps.
JP 2005154599 discloses certain additives useful as aldehyde scavengers. However, such additives are not suitable for PU foam processes.
US 20130203880 discloses the use of polyhydrazodicarbonamides (polyhydrazodicarbonamides) to reduce aldehyde emissions in polyurethane foams. However, it is only effective when large amounts of polyhydrazodicarbonamide are added, which affects the mechanical properties of the PU foam.
After extensive prior art research, none of the documents cited above were found to teach or suggest the present invention.
Summary of The Invention
It has now surprisingly been found that the compositions and methods of the present invention solve the above problems. Advantages of the invention may include: (1) reduced aldehyde emissions, particularly acetaldehyde emissions; (2) the cost is low; and (3) does not significantly affect the mechanical properties of the foam.
The present invention relates to compositions having reduced aldehyde emissions and methods of making these compositions. In one embodiment, the present invention provides a composition for making a polyurethane foam, the composition comprising: (a) a polyfunctional isocyanate; (b) an isocyanate-reactive composition; and (c) a compound of the formula:
wherein
R1 is selected from hydrogen, hydroxy or unsubstituted or substituted C1-C35Alkyl radical, C2-C35Alkenyl, aryl, alkylaryl or C1-C35An alkoxy group,
r2 is selected from a bond or unsubstituted or substituted aryl, C2-C35Alkenyl, alkylaryl, C1-C35Alkoxy or C1-C35An alkyl group, a carboxyl group,
a is an ion having a positive charge,
wherein compound (c) is present in the composition in an amount of about 0.001 to about 10, preferably about 0.01 to about 5, more preferably about 0.05 to about 2 weight percent, based on the total weight of the composition.
In another embodiment, the present invention provides a method of making the foam of the present invention.
In yet another embodiment, the present invention provides a method of forming an interior trim component of a vehicle using a foam made according to the present invention.
Detailed description of the invention
If appearing herein, the term "comprising" and its derivatives are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is disclosed herein. For the avoidance of any doubt, all compositions claimed herein through use of the term "comprising" may include any additional additive, adjuvant, or compound, unless stated to the contrary. Rather, the term "consisting essentially of, if present herein, excludes from any subsequently listed range any other components, steps or procedures other than those which are not necessary for operability, and if the term" consisting of "is used, excludes any components, steps or procedures not specifically described or recited. Unless otherwise specified, the term "or" means the listed members individually as well as in any combination.
The articles "a" and "an" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. For example, "a resin" refers to one resin or more than one resin.
The phrases "in one embodiment," "according to one embodiment," and the like generally refer to a particular element, structure, or feature after the phrase that is included in at least one embodiment of the invention and possibly in more than one embodiment of the invention. Importantly, such phrases are not necessarily referring to the same embodiment.
If the specification states a component or element "may", or "may" be included or have a certain characteristic, that particular component or element does not necessarily have to be included or have that characteristic.
The present invention generally provides a composition for making a polyurethane foam, the composition comprising at least: (a) a polyfunctional isocyanate; (b) an isocyanate-reactive composition; and (c) a compound of the formula:
wherein
R1 is selected from hydrogen, hydroxy or unsubstituted or substituted C1-C35Alkyl radical, C2-C35Alkenyl, aryl, alkylaryl or C1-C35An alkoxy group,
r2 is selected from a bond or unsubstituted or substituted aryl, C2-C35Alkenyl, alkylaryl, C1-C35Alkoxy or C1-C35An alkyl group, a carboxyl group,
a is an ion having a positive charge,
wherein compound (c) is present in the composition in an amount of about 0.001 to about 10, preferably about 0.01 to about 5, more preferably about 0.05 to about 2 weight percent, based on the total weight of the composition.
According to one embodiment, the polyfunctional isocyanate comprises the formula Q (NCO)nThose shown, wherein n is a number of 2 to 5, preferably 2 to 3 and Q is an aliphatic hydrocarbon group having 2 to 18 carbon atoms, a cycloaliphatic hydrocarbon group having 5 to 10 carbon atoms, an araliphatic hydrocarbon group having 8 to 13 carbon atoms or a hydrocarbon group having 6 to 15 carbon atomsAromatic hydrocarbon groups are generally preferred.
Examples of polyfunctional isocyanates include, but are not limited to, ethylene diisocyanate; 1, 4-tetramethylene diisocyanate; 1, 6-hexamethylene diisocyanate; 1, 12-dodecane diisocyanate; cyclobutane-1, 3-diisocyanate; cyclohexane-1, 3-and-1, 4-diisocyanate and mixtures of these isomers; isophorone diisocyanate; 2, 4-and 2, 6-hexahydrotoluylene diisocyanate and mixtures of these isomers; dicyclohexylmethane-4, 4' -diisocyanate (hydrogenated MDI or HMDI); 1, 3-and 1, 4-phenylene diisocyanates; 2, 4-and 2, 6-tolylene diisocyanate and mixtures of these isomers (TDI); diphenylmethane-2, 4 '-and/or-4, 4' -diisocyanate (MDI); naphthalene-1, 5-diisocyanate; triphenylmethane-4, 4',4 "-triisocyanate; polyphenyl-polymethylene-polyisocyanates of the type obtainable by condensation of aniline with formaldehyde, followed by phosgenation (polymeric MDI); norbornane diisocyanate; meta-and para-isocyanatophenylsulfonylisocyanate; a perchlorinated aryl polyisocyanate; a modified polyfunctional isocyanate containing a carbodiimide group, a urethane group, an allophanate group, an isocyanurate group, an urea group or a biuret group; a polyfunctional isocyanate obtained by telomerization; a polyfunctional isocyanate containing an ester group; and a polyfunctional isocyanate containing a polymerized fatty acid group. It will be appreciated by those skilled in the art that mixtures of the above polyfunctional isocyanates may also be used, preferably mixtures of polymeric MDI and mixtures of MDI isomers, more preferably polymeric MDI.
In another embodiment, prepolymers of MDI may also be used as an alternative to MDI. The prepolymer of MDI is prepared by the reaction of MDI and a multifunctional polyol. Methods for the synthesis of prepolymers of MDI are known in the art (see, e.g., Polyurethanes Handbook, 2 nd edition, g. Oertel, 1994).
The isocyanate reactive composition suitable for use in the present invention may comprise a multifunctional polyol or a multifunctional amine.
The multifunctional polyols useful in the present invention may include, but are not limited to, polyether polyols, polyester polyols, biorenewable polyols, polymer polyols, non-combustible polyols, such as phosphorus-containing polyols or halogen-containing polyols. Such polyols may be used alone or as mixtures in suitable combinations.
A common functionality for the multifunctional polyols used in the present invention is from 2 to 6. The molecular weight of the polyol may be 200 to 10,000, preferably 400 to 7,000.
Molecular Weight (MW) is the weight average molecular weight determined by Gel Permeation Chromatography (GPC) using polystyrene as a reference.
The proportion of the polyfunctional polyol is generally from 10% to 90% by weight, preferably from 30% to 80%, based on the composition.
Polyether polyols useful in the present invention include alkylene oxide polyether polyols, such as ethylene oxide polyether polyols and propylene oxide polyether polyols, and polyether polyols having hydroxyl groups derived from polyols, including diols and triols; such as ethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, pentaerythritol, glycerol, diglycerol, trimethylolpropane and similar low molecular weight polyols.
Polyester polyols useful in the present invention include, but are not limited to, those made by reacting a dicarboxylic acid with an excess of a diol, for example adipic acid with ethylene glycol or butanediol, or a lactone with an excess of a diol, for example caprolactone with propylene glycol. In addition, the polyester polyol used in the present invention may further include: linear or lightly branched aliphatic (predominantly adipate) polyols having terminal hydroxyl groups; a low molecular weight aromatic polyester; polycaprolactone; a polycarbonate polyol. These linear or lightly branched aliphatic (primarily adipate) polyols having terminal hydroxyl groups are made by reacting a dicarboxylic acid with an excess of a diol, triol, and mixtures thereof; these dicarboxylic acids include, but are not limited to, for example, adipic acid, AGS mixed acids; these diols, triols include, but are not limited to, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1, 4-butanediol, 1, 6-hexanediol, glycerol, trimethylolpropane, and pentaerythritol. These low molecular weight aromatic polyesters include process residues derived from the production of dimethyl terephthalate (DMT), products commonly referred to as DMT still bottoms (still bottoms), products derived from glycolysis and subsequent re-esterification with diacids or reaction with alkylene oxides of recycled poly (ethylene terephthalate) (PET) bottles or tapes, and products generated by direct esterification of phthalic anhydride. Polycaprolactone is made by ring opening of caprolactone in the presence of an initiator and a catalyst. The initiator includes ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1, 4-butanediol, 1, 6-hexanediol, glycerol, trimethylolpropane and pentaerythritol. Polycarbonate polyols are derived from carbonic acid, which can be prepared by polycondensation of diols with phosgene, by transesterification of diols, usually hexanediol, with carbonates, such as diphenyl carbonate.
Biorenewable polyols suitable for use in the present invention include castor oil, sunflower oil, palm kernel oil, palm oil, canola oil, rapeseed oil, soybean oil, corn oil, peanut oil, olive oil, algae oil, and mixtures thereof.
Examples of multifunctional polyols also include, but are not limited to, graft polyols or polyurea modified polyols. The graft polyol includes a triol in which a vinyl monomer is graft copolymerized. Suitable vinyl monomers include, for example, styrene or acrylonitrile. Polyurea modified polyols are polyols containing polyurea dispersions formed by the reaction of a diamine and a diisocyanate in the presence of a polyol. One variation of the polyurea modified polyol is a polyisocyanate polyaddition (PIPA) polyol, which is formed by the in situ reaction of an isocyanate and an alkanolamine in the polyol.
The non-flammable polyol may be, for example, a phosphorus-containing polyol obtainable by adding an alkylene oxide to a phosphoric acid compound. The halogen-containing polyols may be, for example, those obtainable by ring-opening polymerization of epichlorohydrin or trichlorobutylene oxide.
In a preferred embodiment, the isocyanate-reactive composition is a polyether polyol.
The polyfunctional amines used in the present invention may include polyether polyamines or polyester polyamines.
It was found that the addition of compound (c) to the composition for the production of polyurethane foams according to the invention reduces the aldehyde emissions in the resulting foam.
In one embodiment, R1 is selected from hydrogen, hydroxy or unsubstituted or substituted C1-C35Alkyl radical, C2-C35Alkenyl, aryl, alkylaryl or C1-C35An alkoxy group. In a preferred embodiment, R1 is selected from hydrogen, hydroxy or unsubstituted or substituted C1-C17Alkyl radical, C2-C35Alkenyl or aryl.
In another embodiment, R2 is selected from the group consisting of a bond or unsubstituted or substituted aryl, C2-C35Alkenyl, alkylaryl, C1-C35Alkoxy or C1-C35An alkyl group. In a preferred embodiment, R2 is unsubstituted or substituted phenylene or naphthylene.
In yet another embodiment, a is an ion having a positive charge. In a preferred embodiment, a is an alkali metal cation, an alkaline earth metal cation, a transition metal cation, ammonium or hydrogen ion.
Examples of compounds (c) include, but are not limited to, potassium N- (acetoacetyl) sulfanilate, ammonium 3-acetoacetylamino-4-methoxytoluene-6-sulfonate, 4- [ (1, 3-dioxobutyl) amino ] -benzenesulfonic acid, sodium 4-acetoacetylaminonaphthalene-1-sulfonate, sodium N-acetoacetoxycetaxetine sulfonate, acetoacetyl-p-sulfonamide, 7- [ (1, 3-dioxobutyl) amino ] -3-hydroxynaphthalene-1-sulfonic acid, 3-oxo-N- [4- [ [2- (sulfooxy) ethyl ] sulfonyl ] phenyl ] butanamide, 4- [ (1, 3-dioxobutyl) amino ] naphthalene-1-sulfonic acid, sodium N-acetoacetyl-p-toluenesulfonate, sodium salt, sodium, 7- [ (1, 3-dioxobutyl) amino ] -3-hydroxynaphthalene-1-sulfonic acid ammonium, 2, 5-bis [ (1, 3-dioxobutyl) amino ] benzenesulfonic acid, 2, 5-bis [ (1, 3-dioxobutyl) amino ] -benzenesulfonic acid potassium salt, 5-methoxy-2-methyl-4- (3-oxobutanoylamino) benzenesulfonic acid, bis [3- [ (1, 3-dioxobutyl) amino ] benzenesulfonic acid ] calcium salt, 3- [ [3- [4- (hexadecyloxy) phenyl ] -1, 3-dioxopropyl ] amino ] benzenesulfonic acid sodium salt, 5- [ (1, 3-dioxobutyl) amino ] -1-naphthalenesulfonic acid potassium salt, 5- [ (1, 3-dioxobutyl) amino ] -1-naphthalenesulfonic acid ammonium salt, 2- [4- [ (1, 3-dioxo-3-phenylpropyl) amino ] phenyl ] -1-octadecyl-1H-benzimidazole-5-sulfonic acid, sodium 2, 5-bis (acetoacetylamino) benzenesulfonate, potassium N- (acetoacetyl) sulfanilate, sodium 4-acetoacetaminonaphthalene-1-sulfonate, sodium 6-methyl-2- [4- [ [ 2-oxo-1- [ [ (4-sulfonato) -1-naphthyl) amino ] carbonyl ] propyl ] azo ] -3-sulfonato-phenyl ] benzothiazole-7-sulfonic acid trisodium salt and 7-benzothiazolesulfonic acid-6-methyl-2- [4- [ [2- [ ] [ sodium ], [ 2-oxo-1- [ [ (4-sulfo-1-naphthyl) amino ] carbonyl ] propyl ] azo ] -3-sulfophenyl ] -ammonium sodium salt.
In a preferred embodiment, compound (c) is the ammonium salt of 3-acetoacetylamino-4-methoxytoluene-6-sulfonic acid, the sodium salt of N-acetoacet-cleisidine sulfonate or the potassium salt of N- (acetoacetyl) sulfanilate.
Compound (c) is present in the compositions according to the invention in an amount of from about 0.001 to about 10, preferably from about 0.01 to about 5, more preferably from about 0.05 to about 2 weight percent, based on the total weight of the composition.
According to one embodiment, the NCO index of the composition according to the invention is in the range of about 0.6 to about 1.5, preferably about 0.8 to about 1.3.
In another embodiment, the NCO index of the composition according to the present invention is in the range of about 1.05 to about 10, preferably about 1.05 to about 4.
The isocyanate index or NCO index or index is the ratio of NCO-groups to isocyanate-reactive hydrogen atoms present in the formulation:
[NCO]
[ active Hydrogen ]
In other words, the NCO-index represents the amount of isocyanate actually used in a formulation relative to the amount of isocyanate theoretically required to react with the amount of isocyanate-reactive hydrogen used in the formulation.
Unless otherwise specified, aldehyde emissions were measured according to VDA276 test method (also known as VOC chamber test), which is an emissions measurement method that measures emissions from a foam sample placed in a 1m ethanol chamber where the foam was exposed to 65 ℃ and 5% RH (relative humidity) for several hours. VDA276 (verand Der automotive industrie) is a specific automotive emission process that many automotive OEMs (original equipment manufacturers) use to specify allowable emission levels from automotive interior parts.
In the present invention, the composition according to the present invention may further comprise one or more catalysts to accelerate the reaction between the polyfunctional isocyanate and the polyfunctional polyol, for example amine catalysts such as N, N-dimethylethanolamine, N-dimethyl-N ', N' -bis (2-hydroxypropyl) -1, 3-propanediamine, 2- ((2- (2- (dimethylamino) ethoxy) ethyl) methylamino) ethanol, dimethylcyclohexylamine and triethylenediamine.
In one embodiment, the proportion of catalyst present in the composition according to the invention is from 0.001 to 10% by weight, preferably from 0.1 to 5% by weight.
In another embodiment, the composition according to the invention may further optionally comprise flame retardants, antioxidants, surfactants, physical or chemical blowing agents, chain extenders, crosslinking agents, foam stabilizers, fillers, pigments or any other typical additive for PU materials.
Advantages of the composition according to the invention may include: (1) reduced aldehyde emissions, particularly acetaldehyde emissions; (2) the cost is low; and (3) does not significantly affect the mechanical properties of the foam.
The present invention also provides a method of making a foam using the composition of the present invention, the method comprising mixing components (b) and (c) to form a mixture, and adding the mixture to component (a), wherein compound (c) is present in the composition in an amount of from about 0.001 to about 10, preferably from about 0.01 to about 5, more preferably from about 0.05 to about 2 weight percent based on the total weight of the composition.
Alternatively, a method of making a foam using the composition of the present invention, the method comprising mixing at least components (b) and (c) to form a mixture, and adding the mixture to component (a).
In addition, the present invention also provides a method of forming an interior trim part of a vehicle using the foam according to the present invention (made using the composition of the present invention).
It is also applicable to other industrial fields using Polyurethane (PU) foams. These PU foams include flexible PU foams, semi-rigid PU foams, viscoelastic PU foams, integral skin PU foams, hydroponic (hydro) PU foams, and the like.
The following examples are to be regarded as illustrative of the invention and not as limiting the invention in any way.
Raw material
Isocyanate A SUPRASEC®7007 (polymeric MDI). Suppliers Huntsman, USA;
isocyanate B SUPRASEC®3056. Suppliers Huntsman, USA;
isocyanate C SUPRASEC®2185. Suppliers Huntsman, USA;
-polyol A a trifunctional copolymer of ethylene and propylene oxide having terminal hydroxyl groups derived from glycerol; has a molecular weight of about 5000 g/mol;
-polyol B a trifunctional ethylene glycol-based polyether polyol; has a molecular weight of about 1300 g/mol;
polyol C Daltocel®F428. Suppliers Huntsman, USA;
foam stabilizer TEGOSTAB®B8734 LF2 (silicone based surfactant). Supplier Evonik;
catalyst A JEFFCAT®ZF 10 (amine catalyst). Suppliers Huntsman, USA;
catalyst B JEFFCAT®DPA (amine catalyst). Suppliers Huntsman, USA;
scavenger A is N- (acetoacetyl) sulfanilic acid potassium salt;
scavenger B3-acetoacetylamino-4-methoxytoluene-6-sulfonic acid ammonium salt;
scavenger C N-acetoacetyl-cleisidine sulfonic acid sodium salt;
scavenger D.1, 3-Dimethylacetonatdicarboxylate
DELA diethanolamine
DMEA to dimethylethanolamine.
Example 1
Formulation of
Component A
-isocyanate A
B component
91.1 parts by weight of polyol A
-3 parts by weight of polyol B
0.5 parts by weight of a foam stabilizer
0.2 parts by weight of catalyst A
0.5 parts by weight of catalyst B
0.3 parts by weight of scavenger A
0.5 parts by weight of DELA
0.4 parts by weight of DMEA
-3.5 parts by weight of water.
Procedure for measuring the movement of a moving object
The a and B components were mixed in a (weight) ratio of a: B =1:1.48 and at an index of 1.00 and stirred in a polyethylene vessel to make polyurea (polyuria)/polyurethane foam. The resulting composition was quickly poured into polyethylene bags. The foaming reaction continued and the foam was allowed to rise freely. The foam was cured at room temperature for a minimum of 15 minutes prior to testing and for each formulation approximately 1 kg of foam was made by a manual mix foam procedure for the VDA276 discharge test.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：热塑性聚氨基甲酸酯组成物