JPH0581620B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinyl chloride resin composition that has excellent weather resistance, low-temperature impact resistance, heat deformation resistance, and thermal stability, and can be used under a wide range of processing conditions. Vinyl chloride polymers (hereinafter sometimes referred to as PVC) are used in large quantities in building materials, vehicles, etc. due to their excellent physical properties, flame retardance, chemical resistance, and weather resistance, as well as their economic efficiency. . Many of these products are used outdoors for long periods of time, and many products require a high degree of impact resistance and weather resistance. Up to now, the following methods (1) to (4) have been known as methods for improving the impact strength and weather resistance of PVC. Namely (1) ethylene-vinyl ester copolymer (EVA), ethylene-acrylic acid ester copolymer (EEA), chlorinated polyolefin (CPE)
Method of mixing one or more elastomers such as PVC with PVC (2) EVA, EEA, CPE, ethylene-propylene copolymer (EPR), ethylene-propylene-nonconjugated diene copolymer (EPT), butyl rubber or its chlorinated product (IIR), epichlorohydrin rubber (CHR), (meth)acrylic acid ester-based copolymer (AR), or polyolefin (PE) in the presence of a polymer with a glass transition point of -20°C or lower. A method using a polymer obtained by polymerizing vinyl chloride, (3) EVA, EEA, EPR, EPT, IIR,
A method of mixing a polymer obtained by polymerizing vinyl chloride in the presence of CHR, CPE, AR, PE, etc. with PVC,
(4) EVA, EEA, EPT, EPR, IIR, CPE, AR,
(meth)acrylic acid ester in the presence of PE etc.
A method is known in which PVC is mixed with a polymer obtained by polymerizing one or more polymerizable monomers selected from aromatic vinyl compounds and vinyl cyanide compounds. However, these conventional methods have many problems in actual processing and use, and the current situation is that they are not necessarily at a level that satisfies users. In other words, in method (1), in order to improve the impact resistance of PVC, an elastomer that is semi-compatible with PVC is used, so under normal kneading conditions, dispersion is insufficient and the reinforcing effect is poor. Often does not appear. On the other hand, it is possible to use a type of elastomer that is highly compatible with PVC, but in this case, not only will the impact resistance strength be reduced, but the hardness of the product will also be reduced. Furthermore, according to this method, the softening temperature of the mixture is significantly lowered, so that it is necessary to limit the use temperature of the product to a low level. In addition, examples using EVA have a small impact strength improvement effect, and examples using CPE have poor weather resistance stability. Although weather resistance stability and impact strength can be improved by using both in combination, a decrease in the softening temperature is unavoidable. In the product obtained by method (2), part of the elastomer is chemically bonded to PVC, and the polymer is
Because it is a homogeneous dispersion of PVC and elastomer, it has the advantage that products with high impact values can be easily obtained, and the ratio of elastomer in the polymer can also be reduced, and the softening temperature decreases little.
Excellent weather resistance. However, this polymer has the problem of a narrow processing range in which the impact strength suddenly decreases even if the processing time becomes slightly longer or the heating temperature rises slightly. In addition, in order to obtain this polymer as a powder that is easy to mix with various compounding agents similar to ordinary PVC, it is necessary to dissolve the elastomer in vinyl chloride or to make it into a fine powder during polymerization, which makes the polymerization operation complicated. Become. According to method (3), it is possible to achieve excellent dispersibility of PVC and elastomer more economically than method (2). However, the biggest problem with this method remains that the processing width is narrow. According to method (4), the resulting mixture can be processed over a wide range of processes, so products with high impact strength can be stably manufactured, and the softening temperature decreases little, but the impact strength is stable against weathering. Gender is not always enough. Another problem with this method is that the impact strength varies greatly depending on the type of notch shape. The present inventor has conducted extensive studies on the conventional methods for obtaining weather-resistant and impact-resistant resin products as described above, and has improved the narrow processing width of method (3), which inherently has excellent weather resistance. As a result of research on methods for molding, we found that using a specific graft polymer allows stable molding under a wide range of processing conditions, and also provides good low-temperature impact resistance, weather resistance, and a low softening temperature. The present inventors have discovered that a PVC composition can be obtained that can provide products with high levels of carbon dioxide, and have completed the present invention. That is, the present invention provides vinyl chloride or It is obtained by polymerizing a monomer mixture mainly composed of vinyl chloride, and (A) and (B) are each
5 to 60 parts by weight of a graft polymer of more than 15% by weight and the total amount of (A) and (B) not more than 85% by weight;
The present invention provides a hard resin composition comprising 100 parts by weight of PVC. Used in the graft polymer in the present invention
The content of methacrylic ester in EMA is 5~
75% by weight. If the content of methacrylic acid ester is less than 5% by weight, it is considered a graft polymer.
It has poor compatibility with PVC, and if it exceeds 75% by weight, the glass transition temperature is too high and the impact strength is insufficient. Examples of methacrylic acid esters in EMA include methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, lauryl methacrylate, etc. Methyl methacrylate is preferred in terms of heat deformation resistance and easy availability.
A copolymer of carbon monoxide, vinyl ether, olefin other than ethylene, etc. may be used as a third component together with these methacrylic esters. The melt index (ASTM D-1238) of this copolymer is 0.1 to 300 g/10 min, preferably 1 to 150 g/10 min. In addition, polyethylene (B) includes ethylene homopolymers produced by high-pressure, medium-pressure, or low-pressure methods, copolymers of ethylene with 10% by weight or less of other monomers,
Alternatively, less than 15% by weight of these polyethylenes can be chlorinated products or oriented metal ions, and the melt index value is 0.01 to 50g/
Approximately 10 min can be used. Such polyethylene (B) may be produced in the process of producing a graft polymer by charging ethylene monomer into a polymerization can. With the vinyl chloride polymerized in the presence of (A) and (B), conventional copolymerizable monomers can be used, if desired, in amounts up to 30% by weight in the mixture with the vinyl chloride. Examples include monoolefins, vinyl ethers, (meth)acrylates, vinyl esters, unsaturated acids, unsaturated nitriles, aromatic vinyls, and the like. The graft polymer of the present invention has ethylene-
The content of methacrylic acid ester copolymer (A) and polyethylene (B) is at least 15% each, and the total amount of (A) and (B) is 85% by weight or less. Manufactured. If the amount of (A) is less than 15% by weight, the reinforcing effect as an impact resistance aid will be small, and if the amount of (B) is less than 15% by weight, the range of processing conditions that can provide high impact values will be narrow. Become. Furthermore, when the total amount of (A) and (B) exceeds 85% by weight, the proportion of (A) and (B) that are not chemically bonded to vinyl chloride increases,
Not only will the reinforcing effect be reduced, but the softening point of the composition will be significantly lowered, making it impossible to achieve the object of the present invention. Incidentally, the graft polymer is produced by a conventional method. The shapes of (A) and (B) to be subjected to the polymerization system are not particularly limited, and may be pellets, sheets, veils, powders, aqueous dispersions, or the like. However, (A)
It is difficult to dissolve in vinyl chloride unless it has a specific composition, and the viscosity of the solution is often high, making operation difficult. In order to get
(A) and (B) are preferably applied to the polymerization system as a powder or an aqueous dispersion. This graft polymer is used in an amount of 5 to 60 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of PVC. If it is less than 5 parts by weight, the effect of improving impact strength is small and is not practical, and if it exceeds 60 parts by weight, the softening temperature of the composition will be significantly lowered. The PVC used in the present invention is not particularly limited as long as it is used for ordinary building materials and hard products, but it is usually a homopolymer of vinyl chloride or a copolymer with 80% by weight or more of vinyl chloride. A copolymer with 20% by weight or less of a monomer or a chlorinated product thereof having an average degree of polymerization of about 400 to 1500 as measured by the method of JIS K 6721 is used. If the average degree of polymerization is less than 400, the processability is excellent, but the impact resistance is low, and if it is greater than 1500, the processability is poor. The composition of the present invention may optionally contain a plasticizer, a stabilizer, an ultraviolet absorber, an antioxidant, a lubricant, a pigment,
Regular PVC compounding agents such as fillers and reinforcing agents and
EVA, EEA, CPE, EPR, EPT, IIR, CHR,
Conventional PVC such as AR, polyolefins, graft polymers of vinyl chloride onto these polymers, acrylonitrile-butadiene-styrene copolymers, methacrylic acid-butadiene-styrene copolymers
may contain a polymeric modifier for use. This polymer modifier can be used in an amount of usually up to 30 parts by weight per 100 parts by weight of PVC. Molding of this composition can be carried out in a conventional manner, and the processing conditions can be selected from a wide range. In addition, the obtained molded product exhibits excellent weather resistance, impact resistance, and heat deformation resistance, so it is highly useful as general hard products such as building materials, vehicles, agricultural and fishery materials, etc. Next, the present invention will be explained by examples. In addition,
% and parts are based on weight. Example The raw materials for polymerization shown in Table 1 (unit: g) were charged into a stainless steel autoclave and polymerized at 50° C. for 12 hours, and then the polymer was collected and dried. Next, the resulting polymer was appropriately pulverized or directly passed through an 18-mesh sieve to obtain a graft polymer under the sieve. Next, mix the ingredients shown in Table 2 at the indicated polymerization ratio using a mill roll at 170°C for 3 minutes (mixing condition a), 180°C for 10 minutes (mixing condition b), or 170°C for 6 minutes (mixing condition c). ) A sample sheet with a thickness of 3 mm was prepared by mixing to form a sheet with a thickness of 1 mm, stacking three layers and pressing at 180° C. for 5 minutes. The impact strength (JISK-7111), softening temperature (according to the JISK-6745 Softening Temperature Test Method), and weather resistance (high impact strength and high softening temperature) were measured using a weatherometer (black panel temperature).
Impact strength (JISK-
7111), color tone change (visual observation), and presence or absence of yoking (visual observation)]. The results are shown in Table 2. Table 2 shows that the composition of the present invention provides molded products with excellent impact resistance, weather resistance, heat deformation resistance, etc. even when processing conditions are changed. On the other hand,
For example, for the comparative compositions of Experiment Nos. 5 and 8, the physical properties may be unbalanced depending on the processing conditions, so it is difficult to widely adopt the processing conditions.

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Claims (1)

[Claims] 1 Polymerization of vinyl chloride or a monomer mixture mainly composed of vinyl chloride in the presence of an ethylene-methacrylic acid ester copolymer (A) and polyethylene (B) with a methacrylic acid ester content of 5 to 75% by weight. (A) and (B) are each 15
Vinyl chloride comprising 5 to 60 parts by weight of a graft polymer in which the total amount of (A) and (B) is greater than 85% by weight and 100 parts by weight of a vinyl chloride polymer. based resin composition.