JPS5933603B2 - Foam manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a foam that is non-adhesive under normal conditions. The present invention also provides a good acrylic urethane foam.

Conventionally, urethane foams containing polyether polyols or polyester polyols and polyfunctional isocyanate compounds as main ingredients have been widely used as normally non-tacky foams, but these foams have poor weather resistance and heat resistance. There is.

In addition, acrylic closed-cell thermosetting foam manufactured using radiation is also commercially available, and while this has good weather resistance and heat resistance, it is complicated to work because it requires the use of radiation. There are manufacturing drawbacks in that it is bulky and requires precise handling. In view of the above-mentioned circumstances, the inventors conducted extensive research in order to obtain a normally non-tacky foam that can be easily produced, has excellent weather resistance and heat resistance, and found that a specific acrylic polyol or The inventors investigated a foam using a specific low molecular weight acrylic copolymer containing a hydroxyl group in place of the polyether polyol or polyester polyol, and came up with the present invention.

That is, this invention provides (a) an unsaturated monomer having one hydroxyl group in the molecule, and (b) an acrylic acid alkyl ester or acrylic acid whose polymer or copolymer has a glass transition temperature of -10°C or higher. and (c) a monomer containing at least one methacrylic acid alkyl ester as a main component in a ratio of 5 to 500 moles of the component b monomer per 1 mole of the component a monomer, and (c) the above monomer. 0 for the b component monomer.
Containing 1.8 to 5 hydroxyl groups per molecule obtained by copolymerization in the presence of a chain transfer agent and/or a polymerization initiator containing hydroxyl groups in an amount of 1 to 20% by weight and 750 to 750% by weight. A low molecular weight acrylic copolymer with a molecular weight of 10,000 and a glass transition temperature of -10°C or higher, a polyfunctional isocyanate compound, and at least one blowing agent selected from water, fluorochlorinated hydrocarbon gas, and a silicone compound. This relates to a method for producing a foam that is characterized by obtaining a normally non-adhesive foam using a starting material of It is possible to easily produce a foam that has excellent properties such as cushioning properties, heat insulation properties, and windproof properties.

The reason why the number of hydroxyl groups and molecular weight of the acrylic low molecular weight copolymer are set within the above range is that if it deviates from this range, it will be difficult to obtain a foam with the above-mentioned good properties, and the workability of manufacturing the foam will decrease. This is because it will be damaged.

In addition, the glass transition temperature of this copolymer is set at -10°C or higher because when the temperature is lower than 10°C, the surface of the resulting foam becomes soft and sticky, and if the glass transition temperature is lower than 10°C, the surface of the resulting foam becomes soft and sticky. This is because dust and dirt may adhere to the body surface and impair workability during manufacturing and handling, making it impossible to obtain a foam that is non-adhesive under normal conditions, which is the object of the present invention. The above acrylic low molecular weight copolymer is composed of (a) an unsaturated monomer having one hydroxyl group in the molecule and (b) a polymer and a copolymer thereof having a glass transition temperature of -10°C or higher. a monomer containing at least one type of acrylic acid alkyl ester or methacrylic acid alkyl ester as a main component, and (c)
It can be obtained by copolymerizing the b-component monomer in the presence of the specified amount of a chain transfer agent and/or a polymerization initiator containing a hydroxyl group.

The low molecular weight acrylic copolymer obtained by this method is particularly suitable as a raw material for producing foams with excellent elongation properties.

On the other hand, for example, a copolymer obtained only from components a and b without using a chain transfer agent containing a hydroxyl group and/or a polymerization initiator as component c in the above synthesis method,
Even if it has a predetermined amount of hydroxyl groups in its molecule, it will not give good results to the elongation properties of the foam. Monomers having one hydroxyl group in the molecule of component a include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate,
2-Hydroxybutyl acrylate, 3-chloro-2-
Examples include hydroxypropyl acrylate.

Such a monomer of component a is used in a ratio that allows about 0.8 to 4 hydroxyl groups contained in the monomer to be introduced into the molecule of the finally obtained low molecular weight acrylic copolymer.

In addition, if this monomer is not used and only the b component monomer is used as c
When the components are polymerized or copolymerized in the presence of a chain transfer agent and/or a polymerization initiator, the termination reaction of the polymerization or copolymerization of component b is often a disproportionation termination reaction rather than a coupling termination reaction. Therefore, two functional groups cannot be introduced at both ends of the molecule of the finally obtained low molecular weight acrylic copolymer. Therefore, in the above method, a predetermined amount of hydroxyl groups are introduced into the molecule by using the a component monomer and the c component together. As the monomer containing at least one kind of alkyl acrylate or alkyl methacrylate as a main component, the glass transition temperature of the polymer or copolymer thereof of component b is -10°C or higher, methyl acrylate (glass Transition temperature T
g-3°C), methyl methacrylate (Tg-105°C)
, ethyl methacrylate (Tg-65°C), n-propyl methacrylate (Tg-35°C), butyl methacrylate (Tg-65°C),
In addition to monomers whose polymers themselves have a glass transition temperature of -10°C or higher, such as g-2FC), copolymers that are mixtures of two or more monomers and are copolymerized. Materials having a glass transition temperature of 10° C. or higher can also be used.

In the latter case, a small amount of acrylonitrile, styrene, etc. may be included as a subcomponent. Examples of the chain transfer agent and polymerization initiator containing a hydroxyl group as component c include 2-mercaptoethanol, 4-mercaptoethanol, azobiscyanopentanol, hydrogen peroxide, etc.
By using these, an average of about one hydroxyl group is introduced at the molecular terminal of the acrylic low molecular weight copolymer finally obtained.

And the number of hydroxyl groups introduced by the a component monomer is 0.8
~4 hydroxyl groups, thereby introducing 1.8 to 5 hydroxyl groups into the copolymer molecule. In order to obtain a low molecular weight acrylic copolymer containing a hydroxyl group using each of the above components, the proportion of each component such that the glass transition temperature of this copolymer is -10°C or higher, that is, a Component b is used in an amount of 5 to 500 moles per mole of component, and both are added in an amount of 0.5 to 1 mole of component b.
Copolymerization may be carried out according to a conventional method in the presence of 1 to 20% by weight of component c.

This polymerization is radical polymerization, and a bulk polymerization method or a solution polymerization method can be adopted. In addition, when using a chain transfer agent as the main function of introducing a hydroxyl group as described above, it is acceptable to use ordinary ones such as benzoyl peroxide, α・α7-azobisisobutyronitrile, or redox catalyst as a polymerization initiator. can not use.

Further, the above reaction can be carried out without a solvent, but if desired, a solvent such as n-heptane, toluene, n-hexane, methyl ethyl ketone, ethyl acetate, or isopropanol may be used.

Even when isopropanol is used, chain transfer to isopropanol occurs, making it possible to introduce a hydroxyl group to the end of the molecule. In this invention, the polyfunctional isocyanate compounds used as starting materials together with the above copolymer include tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate,
Included are polyfunctional isocyanate monomers such as xylidene diisocyanate and hexamethylene diisocyanate.

It is also possible to use a known isocyanate prepolymer obtained by reacting this monomer with polyether polyol, polyester polyol, or the like. In this invention, the method of forming a normally non-adhesive foam using the copolymer and polyfunctional compound uses at least one blowing agent selected from water, fluorochlorinated hydrocarbon gas, and a silicone compound. It can be carried out according to the conventional method.

In addition, if chemical blowing agents such as azo compounds, nitroso compounds, and sulfonyl hydrazide compounds that decompose by heating to generate gases such as nitrogen gas and carbon dioxide are used as blowing agents, the radicals generated during the decomposition will cause This is unsuitable because the copolymer decomposes and the strength of the resulting foam decreases. Specific examples of such means are illustrated below. 1. A mixed system using the acrylic low molecular weight copolymer, a polyfunctional isocyanate compound, and a catalyst such as a tertiary amine such as triethylamine or triethylene diamine, or an organotin such as dibutylene dilaurate or dioctyltin dilaurate, A method in which water is added and reacted to generate carbon dioxide gas, causing foaming.

2 Add CCl3F or CCl2F2 to the same mixture system as in 1 above.
A method of adding fluorochlorohydrocarbon gas such as fluorochloride hydrocarbon gas and a silicone compound to cause a reaction and foaming.

Here, the fluorochlorinated hydrocarbon gas acts as a gas generation source, and the silicone compound acts as a foam stabilizer, which is required when the pressure of the gas is too high. 3 A method in which a silicone compound is added to the same mixture system as in 1 above, and the silicone compound is reacted and mechanically foamed.

Here, the silicone compound has the function of contributing to lowering the surface tension of the above-mentioned mixed system (reaction raw materials) and making the above-mentioned foaming substantially possible when foaming is performed by air entrainment by mechanical stirring and mixing. In this sense, it acts as a kind of blowing agent. When using a polyfunctional isocyanate monomer such as the above-mentioned tolylene diisocyanate or diphenylmethane diisocyanate as the polyfunctional isocyanate compound, this monomer is preliminarily mixed with 0 part of the acrylic low molecular weight copolymer. Alternatively, all of the acrylic isocyanate prepolymer is reacted in a proportion equivalent to approximately twice the amount of the hydroxyl group, and this prepolymer or a mixture of this and the rest of the acrylic low molecular weight copolymer, A method of adding a foaming agent similar to 1, 2, and 3 above to cause a reaction and foaming.

In each of these methods, the ratio of the low molecular weight acrylic copolymer to the polyfunctional isocyanate compound is usually in the range of 20 to 250 parts by weight per 100 parts by weight of the copolymer. In addition to the above-mentioned components, the foam of the present invention preferably contains fillers such as calcium carbonate, clay, silica, and barium sulfate, plasticizers, colorants, antiaging agents, antifungal agents, antioxidants, It may contain various commonly used additives such as ultraviolet absorbers, stabilizers, antiozonants, and thixotropic agents, and the type and amount of additives may be determined as appropriate depending on the desired performance and use. Should be decided.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

In the examples, parts mean parts by weight. Example 1 70 parts of methyl methacrylate, 30 parts of butyl acrylate,
15 parts of 2-hydroxyethyl acrylate and 4.6 parts of 2-mercaptoethanol were mixed, and 3 parts of this mixture
0% by weight was placed in a 200CC four-loaf flask, and heated to 70° C. while stirring and passing nitrogen through the flask.

Next, after purging the inside of the flask with nitrogen for about 30 minutes, 0.1 part of azobiscyanopentanol was added, and about 15
Polymerization started after a few minutes and generated heat. After this heat generation became mild, the remaining mixture (70% by weight) was gradually added dropwise into the flask using a dropping funnel over a period of 3 hours, and the polymerization was completed when no heat generation was observed. The acrylic low molecular weight copolymer thus obtained has a solid content (weight change due to heat drying at 130°C for 3 hours).
is 100% by weight, viscosity at 30°C (by B-type viscometer)
is 730 poise, molecular weight (by vapor pressure osmosis method) is 30
00, and the number of hydroxyl groups per molecule (calculated from the acetyl value and molecular weight) was 3.2. 100 parts of the acrylic low molecular weight copolymer obtained by the above method, 75 parts of 2,4-toluene diisocyanate, 0.1 part of DABCO (triethylene diamine manufactured by Haudry Process Co., Ltd.), and 0.3 part of stannath octoate. A foam was produced by the one-shot method (method 1 above) at 20±3° C. using 1.5 parts of L-520 (silicone oil manufactured by Union Carbide) and 4.5 parts of water.

Comparative Example 1 100 parts of polyol GP-3000 (polyether polyol manufactured by Sanyo Kasei Co., Ltd.) was used instead of the acrylic low molecular weight copolymer in Example 1, and all other ingredients were the same as in Example 1. A conventional foam for urethane foam was produced in the same manner as in Example 1.

Comparative Example 2 In the production of the acrylic low molecular weight copolymer of Example 1, 16.9 parts of lauryl mercaptan was used instead of 4.6 parts of 2-mercaptoethanol, and 0.1 part of azobiscyanopentanol was used. An acrylic low molecular weight copolymer was obtained in the same manner as in Example 1, except that 0.1 part of azobisisobutyronitrile was used.

The molecular weight of this copolymer was 2900, and the number of hydroxyl groups per molecule was 2.4. A foam was prepared in the same manner as in Example 1 using 100 parts of this copolymer and with all other formulations being the same as in Example 1. Example 2 After dehydrating the acrylic low molecular weight copolymer obtained in Example 1 by heating under reduced pressure, 34 parts of toluylene diisocyanate was added and reacted at 130° C. for 7 hours.

The acrylic isocyanate prepolymer thus obtained had an isocyanate content (determined by dibutylamine) of 5.2% and a molecular weight of 3,000. 100 parts of this acrylic isocyanate prepolymer, DC-
200 (Silicone oil manufactured by Tau Chemical) 2.5
Part, MOCA (3,3'-dichloro-4, manufactured by DuPont)
4'-diaminodiphenylmethane) 12 parts, FreOn
4 parts of ll (trichlorofluoromethane manufactured by Dupont),
A prepolymer method (above 4.
A foam was produced by method 12).

Comparative Example 3 In place of the acrylic isocyanate prepolymer in Example 2, 100 parts of Adiprene L-100 (prepolymer made of tolylene diisocyanate and polyether polyol manufactured by DuPont) was used, and all other formulations were carried out. A conventional foam for urethane foam was produced in the same manner as in Example 2.

Comparative Example 4 An acrylic isocyanate prepolymer was prepared in the same manner as in Example 2 using the acrylic low molecular weight copolymer produced in Comparative Example 2, and 100 parts of this prepolymer was used to prepare other formulations. All the same as Example 2, Example 2
The foam was produced in the same manner as.

Example 3 70 parts of ethyl acrylate, 30 parts of methyl methacrylate,
An acrylic low molecular weight copolymer was obtained in the same manner as in Example 1 using 2.8 parts of 2-hydroxyethyl acrylate, 1.8 parts of 2-mercaptoethanol, and 0.1 part of azobisisobutyronitrile. .

The molecular weight of this copolymer was 5,000,011 and the number of hydroxyl groups per molecule was 2.1. 100 parts of this acrylic low molecular weight copolymer, 130 parts of Takenate L-1030 (bifunctional isocyanate prepolymer of tolylene diisocyanate and polyether polyol manufactured by Takeda Pharmaceutical Co., Ltd., NCO content 2% by weight), dioctyl phthalate 10 copies, S
4 parts of Hl25O (silicone oil manufactured by Toray Silicon Co., Ltd.) was mixed in a Hobart mixer at a temperature of 20°C at 300 rpm.
The mixture was stirred and mixed for 5 minutes at m, and then subjected to reaction foaming (method 3 above) to produce a foam.

Comparative Example 5 In place of the acrylic low molecular weight copolymer in Example 3, 100 parts of GP-3000 (mentioned above) was used, and all other formulations were the same as in Example 3.
A conventional foam for urethane foam was produced by reaction foaming under the same conditions as described above.

Comparative Example 6 In the production of the acrylic low molecular weight copolymer of Example 3, the number of parts of 2-hydroxyethyl acrylate used was 5.
6 parts and 1.8 parts of 2-mercaptoethanol.
An acrylic low molecular weight copolymer was obtained in the same manner as in Example 3, except that 6.6 parts of lauryl mercaptan was used instead of 6.6 parts of lauryl mercaptan.

The molecular weight of this copolymer was 5100, and the number of hydroxyl groups per molecule was 2.4. A foam was prepared in the same manner as in Example 3 using 100 parts of this copolymer and with all other formulations being the same as in Example 3. Regarding the foams obtained in the above Examples and Comparative Examples, immediately after production (A
) and (B) after accelerated deterioration for 180 hours in a sunshine weather meter. The results are shown in Tables 1 to 3 below.

Claims (1)

[Claims] 1. (a) an unsaturated monomer having one hydroxyl group in the molecule; and (b) an acrylic acid alkyl ester whose polymers and copolymers have a glass transition temperature of -10°C or higher. or a monomer whose main component is at least one type of methacrylic acid alkyl ester, in a ratio of 5 to 500 moles of the component b monomer per 1 mole of the component a monomer, and (
c) 1 per molecule obtained by copolymerization in the presence of a chain transfer agent and/or a polymerization initiator containing a hydroxyl group in an amount of 0.1 to 20% by weight based on the monomer of component b. .8 to 5 hydroxyl groups and 750 to 10,000
An acrylic low molecular weight copolymer with a glass transition temperature of -10°C or higher and a polyfunctional isocyanate compound are used as starting materials, and this is used as a starting material to form a compound selected from water, fluorochlorinated hydrocarbon gas and a silicone compound. 1. A method for producing a foam, which comprises reaction-foaming using at least one blowing agent to obtain a normally non-tacky foam. 2. The method for producing a foam according to claim 1, wherein the polyfunctional isocyanate compound is a polyfunctional isocyanate monomer such as tolylene diisocyanate or diphenylmethane diisocyanate. 3 The functional isocyanate monomer is added in advance to 1 per molecule.
．． Part or all of the low molecular weight acrylic copolymer containing 8 to 5 hydroxyl groups and having a molecular weight of 750 to 10,000 and a glass transition temperature of -10°C or higher is approximately twice equivalent to the hydroxyl group. acrylic isocyanate prepolymer and a mixture of this prepolymer or this prepolymer with the remainder of the acrylic low molecular weight copolymer selected from water, fluorochlorinated hydrocarbon gas, and a silicone compound. 3. The method for producing a foam according to claim 2, wherein at least one blowing agent is added and reaction foaming is carried out. 4. The polyfunctional isocyanate compound is composed of a non-acrylic isocyanate prepolymer obtained by reacting a polyfunctional isocyanate monomer such as tolylene diisocyanate or diphenylmethane diisocyanate with a polyether polyol, polyester polyol, etc. A method for producing a foam according to claim 1. 5 Contains 1.8 to 5 hydroxyl groups per molecule and 7
The glass transition temperature with a molecular weight of 50 to 10,000 is -
20 to 250 parts of polyfunctional isocyanate compound to 100 parts by weight of acrylic low molecular weight copolymer at 10°C or higher.
5. A method for producing a foam according to any one of claims 1 to 4, in which parts by weight are used.