JPH10217358A - Cover for cooler exterior part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the weatherability and durability of a cooler exterior parts cover, and reduce choking, thermal deformation, and thermal discoloration by molding vinylchloride resin composition containing a specific quantity of a UV ray absorption agent, an organic tin heat-stabilizer and a specific hydrotalcite. SOLUTION: A vinylchloride resin composition for molding a cooler exterior part cover has vinylchloride resin having an average polymerization degree of 400-1300 and chlorination vinylchloride resin having an average polymerization degree of 400-1500 of vinylchloride resin before chlorination as a resin component. The added quantity of UV ray absorption agent is 0.01-1 pts.wt., the added quantity of organic tin heat-stabilizer is 1-3 pts.wt., and the added quantity of hydrotalcite is 1-5 pts.wt. with respect to 100 pts.wt. vinylchloride. Hydrotalcite needs to be a composition shown by formula Mg1-x Alx (OH)2 (CO3 )0.5x .mH2 O and, in the formula, (x) and (m) show numbers of 0<x<0.5 and 0<=m<=2 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooler exterior part cover having excellent weather resistance and heat resistance, and having little choking, thermal deformation and thermal discoloration.

[0002]

2. Description of the Related Art Various coolers for business use, industrial use, home use, etc. are installed indoors and outdoors, and the cooler body and parts attached to the cooler are usually covered with molded articles made of synthetic resin. . If the cooler is used outdoors,
Cooler covers and component covers made of synthetic resin molded products (hereinafter referred to as “cooler exterior component covers”) are susceptible to thermal deformation and discoloration because they are directly exposed to sunlight. The appearance of the cooler exterior component cover often changes during use, and often requires replacement of the cooler exterior component cover.

In recent years, there has been a demand for general-purpose resins which are economical and excellent in heat resistance, weather resistance, molding workability, impact resistance and the like. For example, vinyl chloride resin has various excellent properties, but is easily decomposed by heat, and therefore, heat resistance and weather resistance using a heat stabilizer such as a lead-based stabilizer or a tin-based stabilizer are used. Have been attempted. A hard vinyl chloride resin composition containing a lead-based stabilizer is excellent in heat resistance, but has a drawback of chalking (whitening) and discoloration within a relatively short period of time when used outdoors. In addition, chalking,
It is presumed to be based on surface degradation due to light and moisture, the effects of colorants and dispersants, and the bloom phenomenon of additives.

On the other hand, a hard vinyl chloride resin composition containing a tin-based stabilizer is excellent in weather resistance, but has a higher heat softening temperature than a hard vinyl chloride resin composition containing a lead-based stabilizer. Therefore, there is a drawback that a portion which directly receives sunlight undergoes thermal deformation and discoloration such as waving and bending due to thermal expansion. As described above, each case has advantages and disadvantages, and when used outdoors for a long period of time, there arises a problem that chalking, thermal discoloration or thermal deformation occurs.

[0005] In order to solve the above-mentioned disadvantages, a method has been adopted in which various additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, a filler, a coloring agent and the like are blended, and sunlight is shielded. However, no appropriate measures have been found to sufficiently and effectively suppress chalking, thermal discoloration or thermal deformation of the hard vinyl chloride resin composition.

[0006]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to develop a cooler exterior component cover free from chalking, thermal deformation, thermal discoloration and the like.
By using a tin-based heat stabilizer and an ultraviolet absorber in combination,
The present inventors have also found that the above object can be achieved by adding an acrylic rubber substance as needed, and have completed the present invention. That is, the object of the present invention is weather resistance,
An object of the present invention is to provide a cooler exterior part cover that has excellent heat resistance and is less likely to cause chalking, thermal deformation and thermal discoloration.

[0007]

The gist of the present invention is to provide a vinyl chloride resin or a chlorinated vinyl chloride resin.
Vinyl chloride containing 0.01 to 1 part by weight of an ultraviolet absorber, 1 to 3 parts by weight of an organotin-based heat stabilizer, and 1 to 5 parts by weight of hydrotalcite represented by the following chemical formula (1) The present invention is in a cooler exterior component cover formed by molding a resin composition.

Formula 2 Mg _1-x Al _x (OH) ₂ (CO ₃ ) _0.5X · mH ₂ O (1) (where x and m are 0 <x <0.5 and 0 ≦
Indicates the number of m ≦ 2. )

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail. A vinyl chloride resin, which is a resin component of a vinyl chloride resin composition for forming a cooler exterior part cover of the present invention, comprises vinyl chloride or vinyl chloride. The mixture is not particularly limited as long as it is produced by suspension polymerization or bulk polymerization of a mixture with a copolymerizable comonomer.
Those in the range of 300 are preferred. The average degree of polymerization is
If it is less than 400, the impact strength tends to decrease, and if it is more than 1300, the melt viscosity of the resin increases, and it is manufactured by molding methods such as extrusion molding, injection molding, blow molding, compression molding, and powder molding. There is a tendency that the molding processability of the vinyl chloride resin composition to the cooler exterior component cover is inferior.

The chlorinated vinyl chloride resin preferably has an average degree of polymerization of the vinyl chloride resin before chlorination in the range of 400 to 1500, and the chlorination degree is preferably 70% by weight or less. . If it exceeds 70% by weight, the moldability tends to be poor. As the resin component of the vinyl chloride resin composition, a vinyl chloride resin and a chlorinated vinyl chloride resin are used alone or in combination. Hereinafter, these vinyl chloride resins, chlorinated vinyl chloride resins, and mixtures thereof are simply referred to as vinyl chloride resins.

The ultraviolet absorber contained in the vinyl chloride resin composition used in the present invention is, for example, a salicylic acid ultraviolet absorber, a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a cyanoacrylate ultraviolet absorber. In the present invention, a benzotriazole-based ultraviolet absorber is particularly preferably used. The amount of the ultraviolet absorber added is 100 vinyl chloride resin.
The range of 0.01 to 1 part by weight relative to part by weight is appropriate. When the amount is less than 0.01 part by weight, the effect of preventing ultraviolet rays is not sufficient. On the other hand, when the amount is more than 1 part by weight, the effect of preventing ultraviolet rays is not improved in proportion to the addition ratio, which is economically disadvantageous. Become.

The organotin-based heat stabilizer which is one component of the vinyl chloride resin composition used in the present invention includes, for example, di-n-octyltin bis (isooctylthioglycolate), di-n-octyltin Maleate polymer, di-
di-n-octyltin-based stabilizers such as n-octyltin dilaurate, di-n-octyltin maleate, (di-n-octyltin bisalkylmalate), di-n-butyltin Bismaleic acid ester salt, di-
n-butyltin maleate polymer, di-n-butyltin bisoctylthioglycol ester salt, di-n-butyltin-β-mercaptopropionate polymer, di-n
Di-n-butyltin-based stabilizers such as -butyltin dilaurate; and di-n-methyltin-based stabilizers such as di-n-methyltinbis (isooctylmercaptoacetate). Commercially available organic tin heat stabilizers are used.

The amount of the organotin-based heat stabilizer used must be in the range of 1 to 3 parts by weight based on 100 parts by weight of the vinyl chloride resin. If the amount used is less than 1 part by weight, the effect of improving the thermal stability is small, and even if it exceeds 3 parts by weight, the thermal stability is not improved as proportional to the proportion added, which is economically disadvantageous. Becomes

Hydrotalcite is an inorganic substance consisting of basic carbonates of magnesium and aluminum, and various compositions are known. The hydrotalcite added to the composition of the present invention needs to have the composition represented by the chemical formula (1), and may be anhydrous or hydrated. In addition, since hydrotalcite alone has initial coloring and is inferior in heat resistance, it is essential to use an organic tin-based heat stabilizer in combination.

The addition amount of hydrotalcite is suitably in the range of 1 to 5 parts by weight based on 100 parts by weight of the vinyl chloride resin. If the amount of hydrotalcite is less than 1 part by weight, the effect of improving the thermal stability is small. On the other hand, if it exceeds 5 parts by weight, no significant effect on the thermal stability is observed. The addition ratio of the organotin-based heat stabilizer and hydrotalcite is desirably about 1 to 3 with respect to 1 in weight.

It is preferable that an acrylic rubber substance is added to the vinyl chloride resin composition used for molding the cover of the cooler exterior part of the present invention in order to improve the impact resistance of the molded article. The acrylic rubber substance is a synthetic rubber mainly composed of an acrylate, for example, a copolymer of ethyl acrylate and chloroethyl vinyl ether, a copolymer of n-butyl acrylate and acrylonitrile, and a copolymer of ethyl acrylate and acrylonitrile. Copolymers and the like can be used, and many commercial products can be used. The amount of the acrylic rubber substance added is 100 vinyl chloride resin.
It is desirable that the amount be in the range of 3 to 50 parts by weight based on parts by weight. If the amount of the acrylic rubber substance is less than 3 parts by weight, the effect of improving the impact resistance is small, and if it is more than 50 parts by weight, the moldability is poor.

The vinyl chloride resin composition used for molding the cover of the cooler exterior part of the present invention may further contain various known additives as necessary, taking into account the moldability of the cooler exterior part cover, the location of the cooler, and the like. Agents such as lubricants, antioxidants, fillers, foaming agents, coloring agents, antistatic agents, flame retardants, plasticizers, and the like can be added.

To produce a vinyl chloride resin composition,
It is prepared by uniformly mixing a vinyl chloride-based resin, an ultraviolet absorber, an organic tin-based heat stabilizer, hydrotalcite, and, if necessary, the above-mentioned various additives such as an acrylic rubber substance. In order to uniformly mix these components, they are charged into a mixer such as, for example, a Henschel mixer, a ribbon blender, or a planetary mixer, and sufficiently stirred. The above-mentioned mixture may be further kneaded with the vinyl chloride resin composition. For kneading, for example, an extruder, a Banbury mixer, a kneader, or the like, which can be stirred under heating and under a shearing force, is used. The composition after kneading is used after being pelletized by a sheet cut method or a hot cut method.

The vinyl chloride resin composition thus obtained is extrusion-molded, injection-molded, blow-molded, compression-molded into various cooler exterior component covers, for example, a cooler body cover, a pipe protection or coating cover, or the like. It is molded into a desired shape by various molding methods such as powder molding.

[0019]

EXAMPLES Next, the cooler exterior parts cover of the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless departing from the gist thereof. The method for evaluating the cooler exterior component cover is as follows. 1. Weather resistance test (1) Acceleration test Sunshine weatherometer manufactured by Suga Test Instruments Co., Ltd. was used. Carbon arc, no rainfall, after irradiation for 250 hours and 500 hours After color difference (ΔE) measurement and visual judgment of degree of discoloration by Kurashiki Boseki's system outer color ○: no discoloration △: slight discoloration ×: complete discoloration Exposure outdoors for one year to evaluate the degree of chalking ○: None △: Little ×: Many

2. Impact Resistance Test Based on JIS K-7111, measure the Charpy impact strength of a test piece after molding and after irradiation with a sunshine weatherometer at 83 ° C. for 500 hours. A value of 10 kg-cm / cm ² or more is preferable. 3. Heat resistance Vicat softening temperature is measured based on JIS K-7206. A value of 85 ° C. or higher is preferred.

Examples 1 to 6 and Comparative Examples 1 to 4 Vinyl chloride resin (PVC) having an average degree of polymerization of 1100 in the amounts (parts by weight) shown in Table 1 and a degree of polymerization of PVC before chlorination of 69
0, chlorinated vinyl chloride resin (CPV) with a chlorination rate of 64%
C), acrylic rubber (Kane Ace FK, manufactured by Kaneka Chemical Co., Ltd .: rubber), organic tin-based heat stabilizer (KS-45D-1, manufactured by Kyodo Yakuhin: stabilizer), hydrotalcite (Mg _0.67)
Al _0.33 (OH) ₂ (CO ₃ ) _0.165 · 0.5 H ₂ O: Hydro), benzotriazole (ultraviolet absorber: absorber) and polyazo brown (colorant) mixed with a supermixer, resulting composition The material was kneaded for 6 minutes at a temperature of 170 ° C. using a 9-inch diameter mill roll, and a thickness of about 3 mm
Sheet was obtained. Next, the sheet is pelletized by a sheet cutting method, and the pellet is extruded to a thickness of 3 mm.
A U-shaped pipe cover (cooler exterior component cover) having a uniform thickness of 100 mm and a width of 100 mm was manufactured. A test piece was cut out from the flat part of the cooler exterior component cover and subjected to various tests. The evaluation results are also shown in Table 1.

[0022]

[Table 1] *: Benzophenone UV absorber

[0023]

[Table 2]

As is evident from Table 1 (continued), the cooler exterior part cover molded from the vinyl chloride resin composition lacking either hydrotalcite or the organotin stabilizer has poor weather resistance. Particularly, those using a lead-based stabilizer are remarkably choked outdoors, and their use outdoors is restricted.

[0025]

The cooler exterior part cover of the present invention has excellent weather resistance and heat resistance, and does not cause chalking, thermal deformation, thermal discoloration, etc. even when used outdoors, and can be used for a long time. Is now possible.

Claims (5)

[Claims] 1. An ultraviolet absorber, 0.01 to 1 part by weight, an organotin-based heat stabilizer, 1 to 3 parts by weight, and 100 parts by weight of a vinyl chloride resin or a chlorinated vinyl chloride resin, and represented by the following chemical formula (1). A cooler exterior part cover formed by molding a vinyl chloride resin composition containing 1 to 5 parts by weight of the hydrotalcite to be used. Formula 1 Mg _1-x Al _x (OH) ₂ (CO ₃ ) _0.5X · mH ₂ O (1) (where x and m are 0 <x <0.5 and 0 ≦
Indicates the number of m ≦ 2. ) 2. The vinyl chloride resin has an average degree of polymerization of 400 to 1
The cooler exterior component cover according to claim 1, wherein the range is 300. 3. The chlorinated vinyl chloride resin has an average degree of polymerization of the vinyl chloride polymer before chlorination in the range of 400 to 1500 and a chlorination degree in the range of 60 to 70% by weight. The cooler exterior part cover according to claim 1 or 2. 4. The cooler exterior part cover according to claim 1, wherein the ultraviolet absorber is a benzotriazole-based ultraviolet absorber. 5. The cooler exterior part cover according to claim 1, wherein the vinyl chloride resin composition contains an acrylic rubber substance.