JPH04103643A - Vinyl chloride composition for paste processing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a highly foamable plastisol that has excellent resistance to volume reduction due to heat (heat-induced flattening resistance), compression recovery property/surface strength (hereinafter referred to as rubber elasticity), and good viscosity stability. Regarding.

Vinyl chloride resin is preferred for its ease of processing and color matching, and is used in a wide range of applications such as toys, daily necessities, industrial goods, and building materials.

Among such vinyl chloride resins, base vinyl chloride resins are extremely easy to adjust the physical properties of molded products, and complex and delicate molding processes can be performed on a relatively small scale and at low energy costs. In order to be easy to perform and to complete the molding by melting the resin after molding the sol with relatively low viscosity,
It is suitable for high-mix, low-volume production, and from this point of view,
Among vinyl chloride resin molded products, it has unique physical properties and shape, and has generally been used favorably for high value-added molded products.

In the above-mentioned paste processing, the PVC resin powder for paste is basically used together with compounding agents such as stabilizers and fillers.
Dispersion in plasticizers to quickly form a paste dispersion; the resulting dispersion can be used in processes such as slush molding, rotary molding, tip molding, etc. at low shear rates, as well as in spread coating and spray coating. The paste must have appropriate fluidity in a wide range of high shear and speeds, there is little change in paste viscosity over time, gelation progresses at an appropriate speed after molding, and the molding process is finished. It is extremely important that there are no problems with the color tone, texture, or surface shape of the molded product.
A delicate balance of performance is required.

The method of blending a foaming agent into such an attractive resin material, heating it to gel and melt it, and thermally decomposing the foaming agent to diffuse gas in plastigel to obtain a foam is a well-known method. ing.

However, in such a method, the expansion ratio is usually 5 times or less, and a foam with a high expansion ratio of 8 times or more cannot be obtained. The reason for this is that the melt viscosity of vinyl chloride resin begins to decrease as the temperature rises, and the foaming gas generated by heating cannot be contained within the plastigel, and the gas scatters freely from the plastigel, making it difficult to obtain a foam with a high magnification. It is difficult.

In addition, the obtained foam also has weaknesses in that it is significantly inferior in mechanical properties such as compression recovery, heat resistance, and surface strength compared to vulcanized rubber foam, and various attempts have been made to improve this. However, it has not met with sufficient success. For example, research has been conducted on a method of chemically crosslinking vinyl chloride resin during processing (Japanese Patent Publication No. 58-22487) and a method of crosslinking a final molded product or an intermediate molded product of vinyl chloride resin by irradiating it with radiation. However, the crosslinked structure obtained by chemically crosslinking vinyl chloride resin with a crosslinking agent has a low crosslinking density and is hardly effective in improving the mechanical properties of molded products, and it cannot be used. Because the crosslinking agent is limited to a special one, it may be difficult to obtain,
They are often very expensive, and there are many problems in handling, such as being dangerous or having a bad odor. Furthermore, many of them lack compatibility with plasticizers, causing phase separation in plastisols, and other disadvantages. Furthermore, when radiation irradiation is used, not only is the equipment cost high and the molding process restricted, but it is also impossible to adjust the degree of crosslinking of the vinyl chloride molded foam to an appropriate degree.

In addition, attempts have been made to create a high-density foam by blending a third component, a crosslinkable polymer, with a vinyl chloride resin, and to improve the rubber elasticity. For example, crosslinkable compositions in which acrylic rubber having crosslinking points such as hydroxyl groups or epoxy groups are blended with vinyl chloride resin and a foaming agent are also known (Japanese Patent Publication No. 52-20220); Although it dissolves in plasticizers at high temperatures, its solubility is low at room temperature, and it cannot be uniformly dispersed in liquid materials such as plastisol, so the system is unstable and the foam cells are disturbed, making it impossible to obtain a uniform foam. I can't.

Based on a similar idea, consideration has been given to blending thermoplastic polyurethane resin with vinyl chloride resin together with a blowing agent (Japanese Patent Publication No. 58-27818, Japanese Patent Publication No. 59-23730).
However, there is a significant difference in the viscosity of vinyl chloride resin and polyurethane resin when melted, and it is difficult to adjust the viscosity of the entire plastigel to an appropriate level when foaming gas is generated, and the expansion ratio does not increase. Furthermore, low-molecular-weight polyurethane resin is a viscous substance with strong stickiness, making it difficult to add in an appropriate amount and having poor handling properties during work. The viscosity changes greatly, making it unsuitable for plastisol.

Therefore, the present inventors previously developed a polyacrylic acid ester having a functional group that is compatible with vinyl chloride resin and a crosslinking agent that can react with the functional group as a crosslinking component that can be used in plastisol. He developed acrylic acid ester-based gray polymers made by polymerizing them in plasticizers for vinyl resins, and discovered and proposed scales that could be blended with plastisol to significantly improve rubber elasticity (Japanese Patent Publication No. 2-253
No. 83), when it is subsequently made into a paste dispersion, its initial viscosity is as low as possible, and its change over time is small over a long period of time. As a result of intensive research, we have completed the present invention.

Therefore, an object of the present invention is to provide a plastisol which is a high-magnification foam, has excellent rubber elasticity, and has good viscosity stability.

That is, the present invention comprises (A) 100 parts by weight of a vinyl chloride polymer obtained by emulsion polymerization, (B) 1 to 15 parts by weight of a vinyl chloride copolymer having active hydrogen in the molecule, and (C) polyurethane. Copolymer 3 grafted with vinyl chloride
20 parts by weight and (D) crosslinking agent 0.1 to 3 parts by weight, and further contains a blowing agent and a plasticizer, and if necessary, various additives such as stabilizers are added. This invention relates to a highly foamable plastisol with excellent properties.

The vinyl chloride polymer as component (A) used in the composition of the present invention is a vinyl chloride homopolymer or a copolymer containing vinyl chloride as a main component, which is produced by an emulsion polymerization method or a deformation polymerization method. . Examples of the comonomer forming the copolymer include olefins such as ethylene, propylene, styrene, and vinyl esters such as vinyl acetate. The average particle size of the polymer is about 0.1
It is in powder form in the range of ~30 microns. These are available in the market, Kanevinyl Paste PSL-31,
PSH-650, PSH-1,0, PS! 11-3L
PCL-12 (Kanebuchi Chemical Industry Co., Ltd.), Sumi
Lit PX-U, PX-N, PX-GL.

px-o, VX-C (Sumitomo Chemical Industries, Ltd.)
, Zeon G-22, G-43, G-121, G-25,
G-103ZX, G-51, G-37J (
Zeon Corporation), Ryuron R-762,
R-770, R-725, R-750 (Tosoh Corporation), Viniki P-470, R-1069, P
-450,75BXSP -400 (MKV Kasei Co., Ltd.) is commercially available. The average degree of polymerization of these commercially available vinyl chloride polymers for paste is 600.
However, for foaming, the average degree of polymerization is preferably in the range of 800 to 1,500 in view of the balance between the melt viscosity of the vinyl chloride polymer and the decomposition temperature of the blowing agent.

The vinyl chloride copolymer having active hydrogen in the molecule as the component (B) used in the present invention is produced by emulsion polymerization of a vinyl chloride monomer and a heptamer having a hydroxyl group in the molecule. For example, there are copolymers of vinyl chloride hetamine and 2-hydroxyalkyl, especially ethyl acrylate.

This item is also available in the market and is Viniki P-100 (MK
V Kasei Co., Ltd.) with an average degree of polymerization of 1300 and an average particle diameter of about 1 micron. Such a vinyl chloride copolymer is crosslinkable, and its terminal hydroxyl group easily crosslinks with the crosslinking agent of component (D). The usage ratio is 1 to 15 t per 100 parts of vinyl chloride polymer of paste resin.
%, preferably 3 to 10 parts. If the amount is less than 1 part, the initial crosslinking will not proceed, resulting in heat-induced settling at the same time as foaming begins, making it impossible to obtain a molded product with a high expansion ratio.

If the amount exceeds 15 parts, crosslinking will proceed too quickly and the crosslinking density will become too high, resulting in an increase in melt viscosity.
The cells of the foam become rough and the foaming ratio cannot be increased.

The copolymer obtained by grafting vinyl chloride onto polyurethane, which is component (D) used in the present invention, is a resin in which hydroxyl groups remain at the ends of urethane bonds. Polyurethane 1
A copolymer grafted with 1.5 to 2.5 parts by weight, especially about 2 parts by weight of vinyl chloride is preferable, and when the molecular weight is measured by high performance liquid chromatography, it is 100,000 or less in terms of polystyrene, preferably about 90,000. is good. If the ratio of polyurethane to vinyl chloride exceeds 40%, plastisol tends to thicken, which is not preferred. This method for producing a graft copolymer involves dissolving a polyol in a vinyl chloride heptamer, performing graft polymerization, and then reacting with incyanate to obtain a polyurethane graft copolymer of vinyl chloride. Note that the molecular weight of polyurethane has a large influence on the change in viscosity of plastisol over time, and the molecular weight of polyurethane is preferably 30,000 or more and 50,000 or less. If it is less than 30,000, the absorption of the plasticizer in the plastisol will be large, the tendency of the plastisol to thicken will be strong, and the viscosity stability will be poor. Further, when the molecular weight is 50,000 or more, the viscosity stability is good, but the melt viscosity of the resin becomes high and the expansion ratio does not become high. The particle size of the resin used is preferably around 100 microns, and if it is less than 50 microns, the plastisol will thicken.

On the other hand, if the plastisol becomes coarser than 150 microns, depending on the viscosity of the plastisol, it may begin to settle, making it necessary to stir it again before molding. The usage ratio is preferably 3 to 20 parts per 100 parts of the vinyl chloride polymer that is the paste resin.
If 20 parts or more is added, the viscosity tends to increase over time, and at the same time, depending on the viscosity of the plastisol, a sedimentation phenomenon may occur.

If the amount is less than 3 parts, no improvement in rubber elasticity is observed.

As the crosslinking agent for component (D), the above-mentioned component (B) and (
C) Compounds having two or more functional groups in the molecule that can react with the component, such as compounds having isocyanate groups, carboxyl groups, epoxy groups, alkoxyamino groups, hydroxyalkylamino groups, and dibasic There are acid anhydrides, etc.

Examples of the compound having an isocyanate group include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl iso/anate, or a compound having an incyanate group at the molecular end of the above-mentioned polyisonate and a compound having at least bifunctional active hydrogen. There are prepolymers and isocyanates in which the aforementioned polyisonanate groups are blocked with masking agents such as phenol, malonic acid diethyl ester, acetoxime, etc. However, considering the long-term viscosity stability of plastisol, the blocked type incyanate is the most effective. be. The amount of these crosslinking agents used is
Although it varies depending on the type of crosslinking agent used and resin composition, 0
．． 1 to 3 parts by weight is desirable.

Furthermore, the plasticizer used in the present invention may be any common plasticizer used in plastisol.
One or a combination of two or more thereof is possible. Typical plasticizers include phthalate esters and aliphatic ester derivatives, and specifically, dimethyl phthalate and dimethyl phthalate.
Heptyl, di-2-ethylhexyl, diisooctyl, di-n-octyl, dinonyl, diisodecyl, diisodecyl, octyl trimellitate, etc. are plasticizers used in base processing of vinyl chloride resins.

The blowing agent used in the present invention is a normal decomposition type blowing agent, such as azodicarbonamide, p, p'-
Examples include oxybisbenzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, and benzenesulfonyl hydrazide.

These are used in an amount of about 0.5 to IO parts by weight per 100 parts by weight of the resin composition.

Furthermore, the vinyl chloride resin composition of the present invention includes stabilizers, thinners, lubricants, fillers, etc., which are usually added to plastisols.
It goes without saying that it may contain antistatic agents, pigments, etc., and other polymeric resins that are miscible with the vinyl chloride resin plastisol should be contained in an amount of about 20 parts by weight or less per 100 parts by weight of the vinyl chloride polymer. You can also do it. Other miscible resins include those containing vinyl chloride as a copolymer component, such as ethylene/vinyl chloride/vinyl acetate terpolymer;
Acrylic polymers, epoxy resins, polyurethanes come into consideration.

In the present invention, the effect of modifying the foam by using the component (B) and the component (C) together is remarkable.
) Plastisols and foams obtained when any of the components is used alone or when the blending ratio of each component is outside the above range may have poor viscosity stability, insufficient magnification of the foam, or Otherwise, defects appear in either the mechanical rubber elasticity, and a well-balanced plastisol cannot be obtained.

<Examples> Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

(1) Foaming magnification ○Near times or more △: 4 to 6 times ×: 3 times or less (2) Foaming cell condition ○: Cell diameter is uniform at 0.5 m/+++ or less △: Cell diameter is C15 m/! Inconsistent below I - ×: Cell roughness has occurred (3) Compression recovery rate (%) Width 10 W / m, length 20 m / m,
It was cut to a thickness of 1 OTJI/rn, and a load of 3.0 to 9 was applied uniformly for 24 hours to compress it, and the state of recovery after 1 hour of pressure removal was evaluated.

Testing machine: Small deformation testing machine (Ichishima Seisakusho) Test temperature 25°
C ○: Indicates a recovery rate of 80% or more after depressurization △: tt 4Q - Indicates a recovery rate of 80% X: 77
(4) The heat-resistant, flattening foam exhibiting a recovery rate of 40% or less is left in an oven at 200°C for 10 minutes, and then its changes are examined.

○: No change in shape △: Slightly distorted shape ×: Completely distorted shape (5) Plastisol viscosity Plastisol viscosity (25°O): BM type viscometer No. 3 - rotor 6 rotations <Example> As shown in the table Expansion ratio of foam prepared according to the formulation shown,
The results of cell state, compression recovery rate, heat resistance, sol viscosity, and odor are shown in the table below. The number of parts used for each ingredient is based on weight.

Vinyl chloride resin ■ Vinyl chloride resin ■ Acrylic rubber ■ Epoxy resin ■ Dianediamide crosslinking agent [phase] Crosslinking agent 0 Foam stabilizer ■ DOP @ ADCA [phase] Stabilizer Ba/Zn t Sn Crosslinking agent O Expansion ratio Cell state compression Recovery rate Heat resistance Loss Viscosity Immediately // Odor over time The resins and various chemicals used in the above experiment are as follows.

■ Amount of vinyl chloride homopolymerized (emulsion polymerization, degree of polymerization) ■ Vinyl chloride-hydroxyacrylate copolymer (emulsion polymerization,
Degree of polymerization: 1300) ■ Epoxy group-containing acrylic rubber (Toa Paint Door Cron 5A-11OL) ■ Epoxy resin, epoxy equivalent: 184 to 194 g/e
q (Tobu Kasei YD-128) ■ Acrylic resin (M, M, A), (ADEKA Argus BAP-1) ■ Ethylene/vinyl acetate/vinyl chloride tertiary graft polymer (Nippon Zeon Graftomer E) ■ Ethylene/vinyl acetate / Vinyl chloride ternary graph] Polymer (Nippon Zeon Graph 1 Hemer R3) ■ Ethylene/PVC copolymer average degree of polymerization 440 (Tosoh Corporation E-430) ■ Ethylene/PVC copolymer average degree of polymerization 1300 ( Tosoh Corporation E-1300) [Phase] PVC/polyurethane graft copolymer resin, containing 33% urethane (Toagosei Corporation NP-3000)
Particle size: 30 microns ■ PVC/polyurethane graft copolymer resin, containing 45% urethane (Toagosei Co., Ltd. NP-6000) Particle size: 30 microns ■ PVC/polyurethane graft copolymer resin, containing 33% urethane (Tosoh Co., Ltd.) ) K-900F) Particle size 10
0 micron ■ PVC/polyurethane graft copolymer resin, containing 45% urethane (Tosoh Corporation K-750C) Particle size 10
0 micron ■ Polyester thermoplastic polyurethane, average molecular weight 30,000 [Phase] Dioctyl phthalate [Phase] Azodicarbonamide ■ Blocked incyanate (Mitsubishi Kasei Corporation Azostar 200) [Phase] Triazinethiol type (Sanbe Kasei Gisnet PC- 10) [Phase] In triazinethiol type (Daiso Co., Ltd. M-Table-(1)), various compounding agents were added as plastisol modifiers and compared with a comparative example (Experiment No. 9).

When adding acrylic rubber (experiment number 1.2), if the amount added is small, no improvement in expansion ratio or rubber 91i properties can be expected. When the amount added is increased, the expansion ratio and rubber elasticity are improved, but the sol viscosity tends to increase.

When epoxy resin was added (experiment number 3.4), the cell condition and rubber elasticity were improved, but the foaming ratio did not increase to 5 times or more.

In addition of low molecular weight acrylic resin (experiment numbers 5 and 6),
Although the cell state becomes uniform, no improvement in expansion ratio or rubber elasticity can be expected.

The M-10 (Daiso Co., Ltd.) formulation containing a triazinethiol compound (experiment number 8) improved the expansion ratio and rubber elasticity, had a uniform cell state, and had good viscosity stability, but it produced an irritating odor during molding. It has the disadvantage of worsening the working environment as it emits

On the other hand, similar triazinethiol compound disfutsu 1-PC
In experiment number 7 using -10 (Sanbe Kasei), the odor disappeared, but the cell condition worsened and the foaming ratio decreased.

From the results shown in Table 1 above, no compounding agent has been found that can fully satisfy the purpose even if acrylic rubber, Evoquin resin, acrylic resin, or triazinethiol-based crosslinking agent is added.

In Table (2), vinyl chloride copolymers were investigated.

Experiment number 10. In II, we investigated a ternary graftomer of ethylene/vinyl acetate/vinyl chloride as an additive;
The roughness of the cell condition was large, and the magnification of the foam did not exceed 5 times. In addition, the viscosity stability of the sol over time also shows a tendency to increase in viscosity. The ethylene/vinyl chloride copolymer of Experiment No. 12.13 also caused cell roughness, similar to the above ternary graftomer.
The magnification of the foam was 5 times or less.

All formulations with the addition of vinyl chloride/polyurethane graft copolymer resin (experiment numbers 14 to 17) had expansion ratios of 6 times or more and greatly improved rubber elasticity.

In addition, there is no special odor and the handling properties are good.

However, depending on the content of the vinyl chloride/polyurethane graft copolymer resin, the viscosity stability of the sol becomes extremely poor. In particular, in the formulation of experiment number 15, the viscosity immediately after adjustment was 1
The viscosity was 500 cps, but it had increased to over 10,000 cps after 3 hours. The best blend in overall evaluation was Experiment No. 16, in which the proportion of urethane in the vinyl chloride/polyurethane graft copolymer resin was 33% and the particle size of the resin was 100 microns.

In Experiment No. 18, in which thermoplastic polyurethane was added, the expansion ratio and rubber elasticity were improved, but the sol viscosity immediately after adjustment was as high as 6,000 cps, and the viscosity increased over time to 12,000 cps after one week. It cannot be used as

In Table (3), the optimum addition amount was investigated using the best combination formulation (Experimental Example 16) evaluated in Table (2) as a control. In experiment numbers 19 to 24, the blending ratio of vinyl chloride/polyurethane graft copolymer resin/vinyl chloride resin with active hydrogen/crosslinking agent was changed, and 10 parts or more was added compared to the evaluated vinyl chloride/urethane resin Wopest resin. All formulations exhibited a foaming ratio of 7 times or more and a compression recovery rate of 70% or more.

In addition, the formulation in which 8 parts or more of PVC resin containing active hydrogen was added did not lose its shape at all in a heat resistance test at 200° C.

It was found that the viscosity stability of the sol was greatly influenced by the urethane content of the graft copolymer and the particle size of the resin. By the way, the blending ratio of experiment number 16 in Table (3) is 100 parts of paste resin that does not contain active hydrogen, 8 parts of paste resin that contains active hydrogen, vinyl chloride/
Polyurethane graft copolymer resin IO part, crosslinking agent 1.
0 parts, DOP 90 parts, ^DCA 7 parts, stabilizer 3.5
As a result, the foaming ratio was 12 times, the cell condition was uniform under 0.3m/rt+diameter, the compression recovery rate was 90% or more, the heat resistance was 200°C x 1Q, and there was no change in shape, and No peculiar odor is generated, and the sol and viscosity are 1200 cps immediately after adjustment, and the viscosity over time after one week is 160.
There was no tendency for viscosity increase at 0 cps. From the above, the blended composition of the invention has a foaming ratio of 10 times or more, has excellent rubber elasticity, and has good viscosity stability.

Claims (1)

[Claims] 1) (A) Vinyl chloride polymer 1 obtained by emulsion polymerization
00 parts by weight (B) 1 to 15 parts by weight of a vinyl chloride copolymer having active hydrogen in the molecule (C) 3 to 20 parts by weight of a copolymer obtained by grafting vinyl chloride onto polyurethane, and (D) 0 parts by weight of a crosslinking agent. A highly foamed plastisol composition with improved rubber elasticity and good viscosity stability, which further contains a blowing agent and a plasticizer. 2) Component (C) is graft-polymerized at a ratio of 1.5 to 2.5 parts by weight of vinyl chloride to 1 part by weight of polyurethane,
2. The resin composition according to claim 1, wherein the average molecular weight is 100,000 or less, and the polyurethane portion is a polyether-based material having a molecular weight of 30,000 to 50,000 and having a hydroxyl group at the molecular end. 3) The resin composition according to Claims 1 and 2, wherein component (D) has two or more functional groups capable of reacting with active hydrogen in its molecule.