JPH051192A - Soft vinyl chloride resin composition for injection molding - Google Patents

Abstract

(57) [Summary] [Structure] A soft vinyl chloride resin composition for injection molding, which comprises 100 parts by weight of a vinyl chloride resin and the following (a) to (d): (a) a benzophenone resin 2.5 to 6.0 parts by weight of a cyanoacrylate-based ultraviolet absorber, and (b) 0.2 of one or more hydrotalcite-based compounds.
.About.5.0 parts by weight, and (c) one or more of Ba--Zn heat stabilizers in an amount of 0.2 to 4.
5 parts by weight, and (d) the number of parts by weight of the resulting molded product having a hardness (according to JIS K 6301 A-type spring hardness test method) of 85 or more. [Effect] The initial weather resistance and long-term weather resistance of the molded article are excellent, and also the thermal stability during molding by the injection molding method is excellent.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to the weather resistance of a molded article and the heat stability during molding in the field of molding a molded article having a hardness of 85 or more and colored a bright color by an injection molding method. Provided is a soft vinyl chloride resin composition for injection molding, which has excellent properties. More specifically, two characteristics relating to weather resistance when the molded product is colored with a light-colored color as an exterior material for automobiles, building materials for outdoor use, that is, mainly UV or heat of polymer molecules of the molded product. How long does it take without substantial deterioration due to the external environment (hereinafter referred to as long-term weather resistance), or temporary exposure at a very early exposure time (several months) before the start of this substantial deterioration? The degree of discoloration to pale yellow (hereinafter referred to as the initial weathering color resistance) is good, and the heat stability during molding processing in injection molding is good, and these characteristics are excellent. The present invention relates to a soft vinyl chloride resin composition for injection molding, which is suitable for outdoor use.

[0002]

2. Description of the Related Art Vinyl chloride resins are inexpensive and can be easily softened by adding a plasticizer or the like, and are therefore used in large quantities in the fields of automobile parts and building materials. Automotive exterior materials and outdoor building materials are strongly required to have weather resistance because they are exposed to harsh environments for a long period of time, and a soft vinyl chloride resin composition that meets these requirements has been developed. It has been widely used for purposes. These compositions are based on the technology that uses a Ba—Zn heat stabilizer as a heat stabilizer and a benzophenone compound or a cyanoacrylate compound as an ultraviolet absorber. Conventionally, molded products for these applications are colored in black, and in this case, the only technical issue is to improve the long-term weather resistance evaluated by the outdoor exposure test and the sunshine weatherometer test. The degree of the phenomenon of temporary discoloration to pale yellow, that is, the initial weathering tint, was not considered at all very early in the exposure period before the deterioration due to the occurrence of deterioration. However, recently, there has been an increasing demand for using a material colored in a light-colored color for outdoor use, and it has become necessary to attach importance to the overlooked initial weathering tint as well as long-term weathering.

[0003] Further, when a soft vinyl chloride resin composition colored with a hard and bright color of 85 or more is molded by an injection molding method, the thermal stability at the time of molding is low, so that the molded body is exposed to heat. There is a phenomenon of being discolored, but this was not a problem in the use only for black.

[0004]

DISCLOSURE OF THE INVENTION The present invention is an injection molding of a weather resistant soft vinyl chloride resin composition according to the prior art as a material for outdoor use having a hardness of 85 or more by coloring in a light color. It is intended to solve the problem that the properties relating to weather resistance such as initial weathering tint resistance and long-term weather resistance and the thermal stability at the time of molding processing during injection molding are insufficient when molded and used by the method.

[0005]

According to the present invention, (a) a benzophenone-based and / or cyanoacrylate-based ultraviolet absorber is added in an amount of 2.5 to 100 parts by weight of a vinyl chloride resin.
6.0 parts by weight, (b) 1 of hydrotalcite compound
0.2 to 5.0 parts by weight of (1) or more, 0.2 to 4.5 parts by weight of (c) one or more of Ba-Zn heat stabilizers, and (d).
If a soft vinyl chloride resin composition containing a plasticizer in an amount of 85 parts by weight so that the hardness of the obtained molded product is mixed as a material for a molded product colored in a light color for outdoor use, This is because it was found that the properties relating to the weather resistance such as the weather resistance and the initial weathering tint are good, and the thermal stability during the molding process when molding by the injection molding method is good. In addition to the above composition, a copolymer containing methyl methacrylate as a main component and having a concentration of 0.4 g
By blending 1 to 30 parts by weight of a methyl methacrylate-based copolymer having a specific viscosity of 0.5 to 1.5 of 100/100 ml of a toluene solution at 30 ° C. to 100 parts by weight of vinyl chloride resin. It was found that these properties can be further enhanced and that these properties are particularly excellent when a phthalic acid-based plasticizer, a trimellitic acid-based plasticizer or an adipic acid-based plasticizer is used as a plasticizer. It is a thing.

The vinyl chloride resin used in the present invention is
Vinyl chloride resin homopolymerized with vinyl chloride monomer,
A vinyl chloride-based copolymer resin containing 85% by weight or more of vinyl chloride and a partially crosslinked vinyl chloride-based resin containing 2 to 65% by weight of vinyl chloride gel insoluble in tetrahydrofuran. These are used alone or in combination of two or more. To use. Examples of the vinyl chloride-based copolymer resin include vinyl chloride-vinyl acetate copolymer resin and other vinyl chloride-alkyl vinyl ester copolymer resins, vinyl chloride-ethylene copolymer resin, vinyl chloride-propylene copolymer resin and other chloride resins. Copolymer resin of vinyl and olefins, copolymer resin of vinyl chloride and acrylic acid or its ester, copolymer resin of vinyl chloride and methacrylic acid or its ester, copolymer resin of vinyl chloride and alkyl vinyl ether, etc. Can be used. As the partially crosslinked vinyl chloride resin, a partially crosslinked vinyl chloride resin obtained by using a diallyl compound such as diallyl phthalate or a di (meth) acrylate compound such as polyethylene glycol (meth) acrylate as a crosslinking agent is used. it can. Average degree of polymerization of vinyl chloride resin (JIS K 6721)
Is preferably 400 to 1500. If the average degree of polymerization is less than 400, the weather resistance will be low, and if the average degree of polymerization is more than 1500, the melt viscosity during injection molding will be high and the thermal stability during molding will be poor, such being undesirable.

The benzophenone type ultraviolet absorber or the cyanoacrylate type ultraviolet absorber used in the present invention may be used alone or in combination. The amount of the ultraviolet absorber used is in the range of 2.5 to 6.0 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. If the amount used is less than 2.5 parts by weight, the ultraviolet absorption capacity is insufficient,
For this reason, when exposed to an outdoor exposure test or a sunshine weatherometer test, deterioration due to ultraviolet rays significantly progresses. Deterioration due to ultraviolet light proceeds more remarkably when a hydrotalcite compound is used in combination, so it is necessary to increase the amount of the ultraviolet light absorber. That is, in the conventional technique in which the hydrotalcite compound is not used in combination, the benzophenone-based UV absorber or the cyanoacrylate-based UV absorber is added in an amount of 0.2 to 2.
A sufficient effect can be exhibited with the use amount of 0 parts by weight, but in the system in which the hydrotalcite compound of the present invention is used in combination, the use amount of the benzophenone ultraviolet absorber or the cyanoacrylate ultraviolet absorber is vinyl chloride. Resin 100
It should be 2.5 parts by weight or more with respect to parts by weight. On the contrary, even if it is used in an amount exceeding 6.0 parts by weight, the ultraviolet absorbing ability is saturated and the effect of increasing the amount does not appear.

The hydrotalcite compound used in the present invention has a general formula Mg _1-x Al _x (OH) ₂ (CO ₃ ) _{X / 2} · mH ₂ O (0 <x ≦ 0.5, m is a positive value). The number of) is a compound and one or more of these compounds are used. The compound exhibits a very excellent effect as a heat stabilizer for a vinyl chloride resin when used in combination with a Ba-Zn heat stabilizer described later. There are various other heat stabilizers for vinyl chloride resins in addition to these compounds, but the heat stabilizer system of the present invention comprising a combination of a hydrotalcite compound and a Ba—Zn heat stabilizer is used. Other than that should not be used. That is, the tin-based heat stabilizer has an excellent effect of improving the thermal stability of the vinyl chloride-based resin, but reduces the weather resistance. Further, the use of the lead-based heat stabilizer is suppressed from the viewpoint of environmental protection. Further, when only the Ba—Zn heat stabilizer is used alone without using the hydrotalcite compound in combination, the effect of improving the heat stability is insufficient. The amount of the hydrotalcite compound used is 0.2 to 5.0 parts by weight based on 100 parts by weight of the vinyl chloride resin. If the amount used is less than 0.2 parts by weight, the thermal stability of the obtained soft vinyl chloride resin composition will be insufficient, and if the amount used exceeds 5.0 parts by weight, the weather resistance will deteriorate.

The amount of the Ba--Zn heat stabilizer used in the present invention is 0. 0 with respect to 100 parts by weight of the vinyl chloride resin.
2 to 4.5 parts by weight. When the amount used is less than 0.2 parts by weight, the thermal stability of the obtained soft vinyl chloride resin composition is insufficient, and when the amount used exceeds 4.5 parts by weight, Ba-Z
There is a problem that the n-type heat stabilizer blooms on the surface of the molded body.

The plasticizer used in the present invention may be any plasticizer usually used for vinyl chloride resins. That is,
Among the plasticizers such as phthalic acid-based, trimellitic acid-based, adipic acid-based, polyester-based, among these, phthalic acid-based, trimellitic acid-based and adipic acid-based plasticizers are preferable, and phthalic acid-based Most preferred are melitic acid-based plasticizers. These may be used alone or in combination of two or more. The amount of the plasticizer used is determined by selecting an appropriate amount so that the hardness of the obtained molded product is 85 or more.

The soft vinyl chloride resin composition of the present invention comprises
It is preferable to add a copolymer containing methyl methacrylate as a main component. The molecular weight of the copolymer is 0.4 g in concentration.
When expressed as the specific viscosity of a toluene solution of / 100 ml measured at 30 ° C, the value is preferably 0.5 to 1.5. When the specific viscosity is less than 0.5, the kneading effect of the composition becomes insufficient, and when the specific viscosity exceeds 1.5, the melt viscosity of the composition becomes high and the thermal stability at the time of molding during injection molding decreases. The amount of the copolymer used is 100% vinyl chloride resin.
1 to 30 parts by weight is preferable with respect to parts by weight. Usage is 1
If it is less than part by weight, the kneading effect of the composition is insufficient, and if it is more than 30 parts by weight, the melt viscosity of the composition becomes too high, which is not preferable.

[0012]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. Examples 1 to 8 and Comparative Examples 1 to 5 Vinyl chloride resins in the parts by weight shown in Table 1, Table 2 and Table 3,
An ultraviolet absorber, a hydrotalcite compound, a heat stabilizer, a plasticizer, and a methyl methacrylate copolymer were mixed with a ribbon blender and dried. Roll-knead the obtained powdery composition at 175 ° C. for 7 minutes,
A masticated sheet having a thickness of about 2 mm was obtained. This is further 180 ℃
Was hot pressed to prepare a sheet having a thickness of 1 mm. The weather resistance was measured using this sheet. On the other hand, the masticated sheet was cut into a pellet shape by cutting it into a square of about 2 mm, and this was used to evaluate the thermal stability at the time of molding by Brabender Plastograph. The evaluation results are shown in Table 1, Table 2 and Table 3.
As is clear from Table 1, Table 2 and Table 3, the composition of the present invention was excellent in both initial weather resistance and long-term weather resistance, and thermal stability during molding.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

* 1: 2-Hydroxy-4-octoxybenzophenone * 2: Ethyl-2-cyano-3,3-diphenyl acrylate * 3: Trade name of hydrotalcite compounds (Kyowa Chemical Industry Co., Ltd.) * 4 : Diisononyl phthalate Note 5: Diisononyl adipate Note 6: Tri-2-ethylhexyl trimellitate * 1: According to JIS K 6301. * 2: 3 at 83 ° C using a sunshine weatherometer
The degree of discoloration after irradiation for 00 hrs is displayed by the Hunter color difference method according to the following formula. The smaller the ΔE, the smaller the degree of discoloration. ΔE = [(Δa) ² + (Δb) ² + (ΔL) ² ] ^1/2 * 3: 3 at 83 ° C. using a sunshine weatherometer
The degree of discoloration after irradiation for 000 hrs is displayed by the Hunter color difference method according to the following formula. The smaller the ΔE, the smaller the degree of discoloration. ΔE = [(Δa) ² + (Δb) ² + (ΔL) ² ] ^1/2 * 4: Time (minutes) until the start of torque increase according to Brabender Plastograph Chamber temperature: 210 ° C Rotor speed: 100 rpm Pellet filling amount: 60g

[0017]

As described above, the soft vinyl chloride resin composition of the present invention is excellent in both initial weathering and long-term weather resistance of a molded article and thermal stability when molding by an injection molding method. ing.

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Claims (3)

[Claims] 1. A soft vinyl chloride resin composition for injection molding, comprising the following components (a) to (d) per 100 parts by weight of a vinyl chloride resin; (a) benzophenone and / or cyanoacrylate. 2.5 to 6.0 parts by weight of a UV absorber, and (b) 0.2 of one or more hydrotalcite compounds.
.About.5.0 parts by weight, and (c) one or more of Ba--Zn heat stabilizers in an amount of 0.2 to 4.
5 parts by weight, and (d) the number of parts by weight of the resulting molded product having a hardness (according to JIS K 6301 A-type spring hardness test method) of 85 or more. 2. A copolymer having methyl methacrylate as a main component, wherein 100 ml of a toluene solution containing 0.4 g of the copolymer has a specific viscosity of 0.5 to 1.5 measured at 30 ° C.
The resin composition according to claim 1, wherein the methyl methacrylate-based copolymer is 1 to 30 parts by weight. 3. The resin composition according to claim 1, wherein the plasticizer is at least one selected from phthalic acid-based, trimellitic acid-based, and adipic acid-based plasticizers.