JPS5923730B2 - Foamable resin composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to a foamable resin composition for normal pressure foaming.

More specifically, the present invention relates to a foamable resin composition that uses a suspension-polymerized vinyl chloride polymer or copolymer as a main component and that can be foamed at normal pressure to produce a foam that is easy to work with and has an extremely good foamability and feel. Conventionally, in the field of vinyl chloride resin foam leather, suspension polymerization of vinyl chloride polymer or copolymer is used to achieve a foaming ratio of 2 to 6 by normal pressure foaming.
It has about twice the amount of foam. However, there are quality problems such as poor foaming properties, such as the cells of the resulting foam that tend to be coarse and non-uniform, and only those that have a relatively hard feel. On the other hand, it is known that emulsion-polymerized vinyl chloride polymers or copolymers can be used to obtain leather foams, and in this case, compared to the case where suspension-polymerized vinyl chloride polymers or copolymers are used. It has the advantage of having good foaming properties and producing a foam with a soft, deerskin-like feel.

However, on the other hand, it is necessary to use emulsion polymerization products, which are more expensive than suspension polymerization products, and furthermore, because the resulting foamable resin composition is in a paste form, release paper, steel belts, etc. must be used as supports. In addition, the foaming process is complicated, such as gelling the coated material and then foaming it, resulting in poor work efficiency.
Moreover, the resulting foam also has the problem of feel, being somewhat hard in the winter and too soft in the summer. However, as a result of intensive research to solve the above-mentioned problems with vinyl chloride resin foams, the present inventors have found that
By overturning the conventional wisdom that suspension polymerized vinyl chloride resin has a dense and uniform cell structure and cannot produce a foam with a deerskin-like soft feel, we used suspension polymerized vinyl chloride resin. Developed a foaming resin composition that has a denser and more uniform cell structure than when using emulsion-polymerized vinyl chloride resin, and can efficiently produce foam with a deerskin-like soft feel. succeeded in doing so.

That is, the present invention provides (A) 100 parts (by weight, hereinafter the same) of a vinyl chloride polymer or copolymer that does not have active hydrogen in the molecule and that is obtained by suspension polymerization, (B that has active hydrogen in the molecule) 1 to 5 parts of vinyl chloride copolymer, (1 to 5 parts of thermoplastic polyurethane resin and 0.1 to 5 parts of crosslinking agent)
5 parts of a foaming resin composition for normal pressure foaming, further comprising a blowing agent, a stabilizer and a plasticizer.

When the foamable resin composition of the present invention having the specific composition is foamed by the normal pressure foaming method to obtain a foam having a foaming ratio of about 2 to 6 times, a suspension polymerized vinyl chloride resin is used as the main component. Nevertheless, when emulsion polymerized vinyl chloride resin is used, a foam with a dense and uniform cell structure equivalent to or better than that of emulsion polymerized vinyl chloride resin and a deerskin-like soft feel can be obtained. The disadvantage of using vinyl chloride resin, which is that the feel is a little hard in the winter and too soft in the summer, is eliminated, and the advantage is that there is little change in the feel throughout the seasons.

Furthermore, the foamable resin composition of the present invention is not in the form of a paste like foamable resin compositions using emulsion-polymerized vinyl chloride resins, but becomes a self-retaining sheet when calendered or the like, so there is no need to use release paper. It has the advantage of excellent work efficiency. The reason why a foam with excellent foamability and feel can be obtained from the foamable resin composition of the present invention is not fully understood, but the addition of thermoplastic polyurethane resin imparts flexibility and cold resistance, and The vinyl chloride copolymer and thermoplastic polyurethane resin that have active hydrogen in the molecule react with the crosslinking agent to generate an appropriate proportion of crosslinks.
It is thought that the melt viscosity is adjusted to provide a dense and uniform cell structure, and that it does not become excessively soft in the summer, that is, the texture does not change much throughout the seasons. Component (A) used in the present invention, that is, a vinyl chloride polymer or copolymer having no active hydrogen in the molecule obtained by suspension polymerization, is a vinyl chloride monomer alone or a vinyl chloride monomer and an active hydrogen. Typical examples include ordinary vinyl chloride polymers or vinyl chloride copolymers obtained by polymerizing with ethylenically unsaturated compounds that do not contain chloride by a normal suspension polymerization method. Homopolymers of vinyl, copolymers of vinyl chloride and vinyl esters (e.g. vinyl acetate, vinyl propionate, vinyl stearate), copolymers of vinyl chloride and olefins (e.g. ethylene, propylene, butylene, etc.), vinyl chloride and styrene or their Examples include copolymers with derivatives, copolymers of vinyl chloride and vinyl ethers (eg, stearyl vinyl ether, vinyl methyl ether, vinyl ethyl ether, etc.).

In addition, the average degree of polymerization of these vinyl chloride polymers or copolymers is in the range of 300 to 3,000, and from the viewpoint of workability and physical properties of the resulting foam, it is 700 to 190.
A value in the range of 0 is preferred. Component (B) used in the present invention, that is, a vinyl chloride copolymer having active hydrogen in the molecule, is a vinyl chloride monomer and a monomer having active hydrogen in the molecule, such as a monomer having a hydroxyl group, a carboxyl group, etc. Products obtained by copolymerization by ordinary suspension polymerization method, emulsion polymerization method, bulk polymerization method, or solution polymerization method can be cited. Typical examples of these include vinyl chloride monomer and 2-hydroxyethyl acrylate. , 2-hydroxyethyl methacrylate, 2-
Hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-chloro-2hydroxypropyl methacrylate, 3-hydroxybutyl acrylate, ethyl-2-hydroxyethyl fumarate, 3-hydroxybutyl vinyl ether, acrylic acid, methacrylic acid, monobutyl maleate, Examples include vinyl chloride copolymers with undecylenic acid and the like.

The vinyl chloride copolymer having active hydrogen in the molecule contains 0.3 to 20 mol% of a comonomer having active hydrogen in the molecule, that is, a comonomer having a hydroxyl group, a carboxyl group, etc. , preferably 0.
Those copolymerized in a range of 5 to 10 mol % are preferably used, and as a result, the melt viscosity during cell formation is less affected by crosslinking, and the foam has a dense and uniform cell structure. It will be done. If the copolymer composition ratio of monomers having active hydrogen in the molecule is more than 20 mol%, the excellent physical properties of the vinyl chloride polymer will be impaired, and if it is less than 0.3 mol%, crosslinking will be insufficient. ,
Therefore, a foam having a dense and uniform cell structure cannot be obtained, and this leads to a decrease in feel in the summer and a decrease in recovery properties (resilience), both of which are undesirable. In addition, as the vinyl chloride copolymer having active hydrogen in the molecule used in the present invention, the vinyl chloride copolymer having no active hydrogen in the molecule can be chemically treated to form hydroxyl groups or carboxyl groups in the molecule. Also included are vinyl chloride copolymers into which a functional group having an active hydrogen is introduced. Examples of methods for chemically treating the vinyl chloride copolymer to introduce functional groups having active hydrogen such as hydroxyl groups and carboxyl groups include a method of hydrolyzing a vinyl chloride-vinyl ester copolymer, and a method of hydrolyzing a vinyl chloride-vinyl ester copolymer; A method of hydrolyzing an acrylic acid ester copolymer, a method of acid-treating a copolymer of vinyl chloride and a vinyl monomer having an epoxy group to open the epoxy group, and a method of copolymerization of vinyl chloride and N-alkoxymethylacrylamide. A method such as hydrolyzing a polymer is adopted. Further, in the present invention, the vinyl chloride copolymer having active hydrogen may be produced on the spot during preparation of the composition of the present invention.

For example, copolymers of vinyl chloride and N-alkoxymethylacrylamide, copolymers of vinyl chloride and vinyl monomers having epoxy groups, etc. are used as they are without chemical treatment, and hydroxyl groups are generated by mechanochemical reaction during kneading and molding. At least it can be used. The average degree of polymerization of the vinyl chloride copolymer having active hydrogen in the molecule used in the present invention is in the range of 300 to 30,000, preferably 700 to 1,900.

When the average degree of polymerization of the polymer is greater than 3,000, workability becomes poor and kneading at high temperatures or for a long time is required, which tends to induce initial decomposition of the blowing agent;
When the size is smaller, it is difficult to obtain a foam that is satisfactory in terms of cell structure and feel, and both are unfavorable. The zero component (ie, thermoplastic polyurethane resin) used in the present invention is
A linear polyurethane with active hydrogen in the molecule,
Both polyether type and polyester type can be used.

Preferred examples include those that have a hydroxyl group at the molecular end and can be reacted with the crosslinking agent described below, which are obtained by reacting a bifunctional polyol and a diisocyanate at a molar ratio of NCO/0H of 1. Its average molecular weight is 3,000 to 300,000, preferably 10,000
~100,000 and a Vicat softening point of 170°C or less is used. When the average molecular weight of the thermoplastic polyurethane resin used is larger than 300,000 and the Vicat softening point is higher than 170 ° C., the compatibility with the vinyl chloride polymer used as the eighth component and component (B) is poor.
When the average molecular weight is less than 3,000, the soft feel and rebound properties of the resulting foam are poor, and it is difficult to obtain a deerskin-like feel, both of which are unfavorable. In the present invention, the aforementioned component I and component Q are each used in a ratio of 1 to 5 parts per 100 parts of component A.

By using component (A), component (B), and component (O) in the above-mentioned specific proportions, a foam with good workability, a dense and uniform cell structure, and an excellent feel can be obtained. If the proportion of component B) used is more than 5 parts, a dense and uniform cell structure can be obtained, but it is economically disadvantageous; on the other hand, if it is less than 1 part, the cell adjustment effect cannot be exhibited due to insufficient crosslinking. A foam with excellent foamability and feel cannot be obtained, and both are undesirable. (If the proportion of the q component used is more than 5 parts, it is economically disadvantageous because the polyurethane resin is expensive; Alternatively, since it is commercially available in the form of pellets, it has poor dispersibility and it is difficult to obtain a uniform foamable resin composition.On the other hand, if the amount is less than 1 part, a deerskin-like soft feel and good recovery properties cannot be obtained. None of these are preferable.The ratio of component (B) and component (0) used is preferably in the range of 2 to 5 parts per 100 parts of component (A), which improves foamability (cell density,
Foams with better uniformity) and deerskin feel can be obtained more economically and with better workability. Used in the present invention (
As the crosslinking agent for the D component, (a vinyl chloride copolymer having active hydrogen in the molecule for the L component and a compound having two or more functional groups in the molecule that can react with the thermoplastic polyurethane resin for the Q component) Compounds and compounds having an isocyanate group, a blocked isocyanate group, a carboxyl group, a hydroxyl group, an epoxy group, an alkoxyalkylamino group, a hydroxyalkylamino group, an amino group, an alkyl mono- or di-substituted amino group in the molecule, Basic acid anhydrides and the like are used.

Typical examples thereof include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, or a compound having at least bifunctional active hydrogen in combination with the polyisocyanate (for example, trimethylolpropane, pentaerythritol, glycerin, polyethylene glycol,
(polytetramethylene glycol, polyethylene adipate, etc.), the isocyanate groups of the polyisocyanate and the initial addition polymer are combined with phenol, diethyl malonate, acetoacetate, acetoxime, acidic sulfite. Blocked isocyanates blocked with soda and various other masking agents, succinic acid, glutaric acid, adipic acid, phthalic acid, phthalic anhydride, cyclohexanedicarboxylic anhydride, triglycidyl isocyanurate, epoxy resins, triethylenetetramine, methylolmelamine, butoxy Examples include methylmelamine, and blocked isocyanates are particularly preferred. The amount of these crosslinking agents used is
Although it varies depending on the type of crosslinking agent used and the resin composition, (0.1 to 5 parts per 100 parts of component A, preferably 0.
．． A range of 3 to 4 parts is employed.

When the amount of crosslinking agent used is more than 5 parts, it is economically disadvantageous and the effect of improving foamability and feel is small, and in some cases, foaming is inhibited by crosslinking, and when it is less than 0.1 part. The cells tend to become rough due to lack of crosslinking, and the rubber elasticity is poor, making it impossible to obtain a product with good recovery properties and feel, which are both unfavorable. As the blowing agent used in the present invention, ordinary decomposable blowing agents can be used as appropriate without any restrictions, such as azodicarbonamide, p.p'-oxybisbenzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide. , benzenesulfonyl hydrazide, etc., and these may be used alone or in combination of two or more.

In particular, azodicarbonamide is preferably used. The amount of blowing agent used is 0.5 parts per 100 parts of component (A).
A range of from 7 parts to 7 parts, preferably from 2 to 5 parts, is employed, whereby a foam with a dense cell structure, uniform foamability, and excellent feel can be obtained with a foaming ratio of about 2 to 6 times. When the amount of blowing agent used is more than 7 parts, the amount of gas generated by thermal decomposition of the blowing agent is too large, so the expansion ratio becomes too large, the strength of the foam itself becomes weak, and it is less than 0.5 parts. This results in an insufficient amount of decomposed gas, making it difficult to obtain a foam that is soft and has a good feel, both of which are undesirable. Examples of the stabilizer used in the present invention include metal compounds such as lead, zinc, cadmium barium, sodium, potassium, calcium, lithium, and tin, and in particular, composite stabilizers thereof and organic stabilizers such as epoxy compounds.

The amount of stabilizer used is 1 per 100 parts of component (A).
A range of 5 parts, preferably 2 to 3 parts is employed. When the amount of the stabilizer used is less than 1 part, the vinyl chloride polymer tends to deteriorate due to heat, and when it is used more than 5 parts, it is uneconomical and undesirable. Another feature of the present invention is that the crosslinking and foaming properties of the resin component are not affected by the type of stabilizer used, and the foamed resin is mainly made of vinyl chloride polymers having active hydrogen such as hydroxyl groups and carboxyl groups. Surubai no Gotoku Ba-
It is not necessary to select and use only Zn-based stabilizers; Ba
Zn-based as well as Ca-Zn-based, Na-Zn-based, K-Z
Most stabilizers such as n-based, Li-Ba-Zn-based, and Li-CaBa-based stabilizers can be used without causing undesirable phenomena such as cell roughness and thermal discoloration, thus expanding the manufacturing conditions for foams. , is industrially preferred.

Examples of the plasticizer used in the present invention include phthalic acid diesters such as dioctyl phthalate, dibutyl phthalate, and dinonyl phthalate, aliphatic dibasic acid esters such as dioctyl adipate and dioctyl sebacate, tricresyl phosphate, and trioctyl phosphate. Examples include phosphoric acid triesters such as, epoxy plasticizers such as epoxidized soybean oil, and polyester plasticizers such as polyethylene adipate.

The amount of plasticizer used is 3 parts per 100 parts of component (A).
A range of 0 to 150 parts, preferably 50 to 120 parts is employed. When the amount of plasticizer used is outside the above range, it is difficult to obtain a foam having a dense and uniform cell structure, a deerskin-like soft feel, and excellent recovery properties, which is not preferable. The foamable resin composition of the present invention is a composition in which a blowing agent, a stabilizer, and a plasticizer are blended with the above-mentioned specific components (A), (B), (O and D), and other organic components. Coloring agents such as dyes, organic pigments, and inorganic pigments may be added as appropriate.

The foamable resin composition of the present invention has the above specific (A) to (D)
It is prepared by mixing the ingredients, foaming agents, stabilizers, plasticizers, and other additives as necessary using a lipon blender, pickling machine, pen shell mixer, etc., and kneading with a mill roll or Banbury mixer. Ru. This is fed to a calender roll or an extruder to form a sheet at a temperature below the decomposition temperature of the blowing agent, and then heated under normal pressure at a temperature of, for example, 180 to 250'C for about 30 seconds to 4 minutes to form the blowing agent. By decomposing the foam, a foam having a foaming ratio of about 2 to 6 times can be obtained. As described above, when the present invention uses emulsion polymerized vinyl chloride resin, wasteful auxiliary materials such as release paper are required and the cell structure can only be manufactured using methods with low work efficiency. A uniform foam with a soft feel and good recovery properties can be produced with extremely high efficiency from suspension polymerized vinyl chloride resin by normal pressure foaming using calendar processing, etc., and the quality of the resulting foam is better than emulsion polymerization. It is industrially extremely advantageous because it is no better than the method using vinyl chloride resin. Since the foam obtained from the foamable resin composition of the present invention has an extremely good feel, it can be used not only as foamed leather for clothing, bags, furniture, etc., but also as wall covering material, etc. Furthermore, the combination of polyurethane resin provides superior cold resistance, oil resistance, abrasion resistance, etc. compared to ordinary vinyl chloride resin foams, so the range of application is extremely wide.

Next, the foamable resin composition of the present invention will be explained with reference to Examples and Comparative Examples.

Example 1 and Comparative Examples 1 to 3 The other components shown in Table 1, excluding the blowing agent, were mixed in a lipon blender, and then sent in fixed amounts to a Banbury mixer to be kneaded and gelled, and then transferred to a mixing roll. The mixture was fed, a foaming agent was added thereto, and the mixture was thoroughly kneaded at 150°C to obtain a foamable resin composition.

The composition was sent to a warming roll and continuously kneaded, taken out as a sheet, laminated on a base fabric using a calendar, and further plasticized and rolled at 150°C to give a foamable resin layer with a thickness of 0.25 mm. This sheet is sent through a cooling drum to a foaming furnace maintained at 220°C.
It was heated for 1 minute and 20 seconds to foam. The foaming ratio, cell condition, and feel of the obtained foamed sheet were determined.

The results are shown in Table 1. The above physical properties were determined as follows. Cell condition: ○ mark: Cell diameter is 0.3 mm or less and uniform △ mark:
A part of the cell is destroyed (X mark): The cell is noticeably rough and the cell diameter is uneven.○ mark: It has an extremely soft feel similar to that of a deerskin, and has elasticity after bending. Excellent recovery properties △: Slightly poor soft feel and elasticity, slightly poor recovery after bending ×: Poor soft feel and elasticity, poor recovery after bending From Table 1, A composition in which a suspension polymerized vinyl chloride polymer was used alone as the foaming resin (Comparative Example 1), a composition in which only a vinyl chloride copolymer having active hydrogen was blended with a suspension polymerized vinyl chloride polymer (
Comparative Example 2) and a composition in which only thermoplastic polyurethane was blended with a suspension polymerized vinyl chloride polymer (Comparative Example 3) did not give foams with good cell condition and feel, but the foaming resin of the present invention A composition using the above three components as (
It can be seen from Example 1) that a foam with very good cell condition and feel can be obtained.

Examples 2 to 4 and Comparative Example 4 Foamed sheets were obtained in the same manner as in Example 1, except that the blending composition was changed to that shown in Table 2.

The results are shown in Table 2. From Table 2, it can be seen that if the amount of component (B) used is less than 1 part per 100 parts of component (B), a foam that is fully satisfactory in terms of cell condition and feel cannot be obtained.

Dou*
Examples 5 to 7 and Comparative Examples 5 to 6 Foamed sheets were obtained in the same manner as in Example 1, except that the compositions were changed to those shown in Table 3.

The results are shown in Table 3. From Table 3, (the amount of component O used is 1 part or more per 100 parts of component (A), the amount of component (]) used is 0.1 part or more per 100 parts of component A, especially 0.5 part. The above is preferable from all aspects of foaming ratio, cell state and feel, and also (B) component, (0 component and (
It can be seen that as the amount of component D used approaches the upper limit of the range of the present invention, foaming is suppressed due to crosslinking, and the composition becomes uneconomical and disadvantageous.

Claims (1)

[Scope of Claims] 1 (A) 100 parts by weight of a vinyl chloride polymer or copolymer having no active hydrogen in the molecule obtained by suspension polymerization, (B) a vinyl chloride type having active hydrogen in the molecule 1 to 5 parts by weight of copolymer, (C) 1 part of thermoplastic polyurethane resin
5 parts by weight of (D) a crosslinking agent, 0.1 to 5 parts by weight, and a foaming agent, a stabilizer, and a plasticizer. 2. The resin composition according to claim 1, wherein component (B) is a vinyl chloride copolymer having a hydroxyl group or a carboxyl group in the molecule. 3. The resin composition according to claim 1 or 2, wherein component (C) is a linear polyurethane having active hydrogen in the molecule. 4 Linear polyurethane with active hydrogen in the molecule is 2
4. The resin composition according to claim 3, which is a reaction product of a functional polyol and a diisocyanate and has a hydroxyl group at the end of the molecule. 5. The resin composition according to claim 1, 2, 3, or 4, wherein component (D) has two or more functional groups capable of reacting with active hydrogen in its molecule.