JPH0337580B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention can employ a wide range of processing conditions, and
The present invention also relates to a hard resin composition that provides high impact strength and excellent weather resistance. Vinyl chloride polymer (hereinafter referred to as PVC) is
In addition to its excellent physical properties, flame retardance, chemical resistance, and weather resistance, it is also used in large quantities in building materials and vehicles due to its economic efficiency. Many of these products are used outdoors for long periods of time, and many products are required to have both high 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℃ or lower. A method using a polymer obtained by polymerizing vinyl, (3) EVA, EEA, EPR, EPT, IIR, CHR,
A method of mixing a polymer obtained by polymerizing vinyl chloride in the presence of CPE, AR, PE, etc. with PVC, (4) EVA,
Polymerization of one or more polymerizable monomers selected from (meth)acrylic acid esters, aromatic vinyl compounds, vinyl cyanide compounds in the presence of EEA, EPT, EPR, IIR, CPE, AR, PE, etc. A method is known in which the polymer obtained by this process is mixed with PVC. 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 impact resistance, an elastomer that is semi-compatible with PVC is used, so under normal kneading conditions, dispersion is insufficient and no reinforcing effect appears. There are many things. 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. The product obtained by method (2) (as an elastomer)
Products using EVA, EEA, or EPR are commercially available), because part of the elastomer is chemically bonded to PVC, and the polymer is a uniform dispersion of PVC and elastomer. It has the advantage of being able to obtain a product with a high impact value, and the proportion of elastomer in the polymer can also be reduced.
It also has a small decrease in softening temperature and has 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, this polymer can be
In order to obtain a powder that is easy to mix with various compounding agents similar to PVC, the elastomer must be dissolved in vinyl chloride or pulverized during polymerization, making the polymerization operation complicated. According to method (3), it is possible to achieve excellent dispersibility of PVC and elastomer more economically than method (2), and as an elastomer,
There are many examples of products using EVA being commercialized. but,
The narrow processing width remains the biggest problem with this method as well. In method (4), an AR emulsion is used as the elastomer, and the monomer is polymerized in one or more stages in the presence of the AR emulsion, and the powdered polymer obtained is commercialized as an acrylate impact additive. There are many examples of this. According to this method, since the mixture can be processed over a wide range, products with high impact strength can be stably produced, and the softening temperature decreases little, but the weather resistance stability of impact strength is not necessarily sufficient. Another problem with this method is that the impact strength varies greatly depending on the type of notch shape. The present inventor has diligently studied methods for obtaining conventional weather-resistant and impact-resistant resin products as described above, and
As a result of research into methods to improve the narrow processing width of method (3), which inherently has excellent weather resistance, we found that using a specific graft copolymer allows stable molding under a wide range of processing conditions. The present inventors have discovered that it is possible to obtain a composition that can provide a PVC resin product that has good weather resistance and a high softening temperature, and has completed the present invention. That is, the present invention provides (1) ethylene-vinyl ester copolymer (EVA) or ethylene-acrylic acid ester copolymer (EEA) (A) and polyethylene
A product obtained by polymerizing vinyl chloride or a monomer mixture (C) mainly composed of vinyl chloride in the presence of (B), in which each of (A) and (B) is more than 15% by weight, and 5 to 60 parts by weight of a graft copolymer () in which the total amount of (A) and (B) is 85% by weight or less, 0.5 to 20 parts by weight of a methyl methacrylate polymer (), and PVC ()
100 parts by weight, and (2) EVA or EEA (A), polyethylene (B) and methyl methacrylate polymer ().
obtained by polymerizing vinyl chloride or a monomer mixture (C) mainly consisting of vinyl chloride in the presence of , and the total amount of (A) and (B) in the polymer part excluding (). is more than 15% by weight each, and the total amount of (A) and (B) is not more than 85% by weight.
The present invention provides a hard resin composition characterized in that, per part by weight, the polymer portion in (') excluding () is 5 to 60 parts by weight, and () is 0.5 to 20 parts by weight. EVA or EEA (A) used in the production of the graft copolymer () or (') in the present invention has an ethylene content of 20 to 80% by weight. If the ethylene content is less than 20% by weight, the glass transition point is too high and the impact strength is insufficiently developed, and if it exceeds 80% by weight, the compatibility with vinyl chloride becomes poor. Examples of vinyl esters in EVA include vinyl acetate, vinyl propionate, vinyl laurate, etc., and examples of acrylates in EEA include methyl acrylate, ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, hydroxypropyl Examples include acrylate, 2-ethylhexyl acrylate, and the like. A copolymer of carbon monoxide, vinyl ether, olefin other than ethylene, etc. may be used as a third component together with these vinyl esters and acrylic esters. 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, or 15% of these polyethylenes. weight%
Examples include chlorinated compounds and metal ion compounds with a melt index value of about 0.01 to 50 at 190°C. 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, and the like. Graft copolymers () and (′) of the present invention
(In the case of ('), the content of EVA or EEA (A) and polyethylene (B) in the polymer part excluding ()) is at least 15% each, and ( It is manufactured so that the total amount of A) and (B) is 85% by weight or less. If the amount of (A) is less than 15% by weight, the reinforcing effect as an impact auxiliary agent will be small, and if the amount of (B) is less than 15% by weight, the range of processing conditions that give high impact values will be narrow. Become. Also, (A)
If 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, which not only reduces the reinforcing effect but also softens the composition. This results in a significant decrease in the score, which does not meet the purpose of the present invention. Incidentally, the graft copolymers () and (') are 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) 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, so () or (') is not recommended. In order to obtain powders that are easily mixed with PVC (), it is preferable to provide (A) and (B) to the polymerization system as powders or aqueous dispersions. The polymer portion of this graft copolymer () or (′) excluding () is PVC () 100
It is used in an amount of 5 to 60 parts by weight, preferably 10 to 50 parts by weight. If the amount is less than 5 parts by weight, the effect of improving impact strength will be too small to be practical;
If the amount exceeds 1 part by weight, the softening point of the composition will decrease significantly. As the methyl methacrylate polymer (), one containing 40% by weight or more of the methyl methacrylate component is used. Specific examples include methyl methacrylate as the main ingredient, and in addition, (meth)acrylic acid esters, aromatic vinyl compounds, vinyl cyanide compounds, etc. (in some cases, a small amount of polyfunctional compounds having two or more unsaturated bonds) Examples include polymers with a gel content of less than 50% by weight, which are obtained by one-stage or multi-stage emulsion copolymerization of acrylic acid monomers, allyl compounds, etc.). Among these, preferred are polymers in which 50% by weight or more of the non-gel portion has a molecular weight of 100,000 or more. Other specific examples include block copolymers in which at least one component is methyl methacrylate. Methyl methacrylate polymer (), including when included in the graft copolymer ('),
It is blended in an amount of 0.5 to 20 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of PVC ().
If it is less than 0.5 part by weight, the strength of the composition tends to be insufficient at the initial stage of kneading, and secondary processability such as vacuum formability deteriorates. On the other hand, if it exceeds 20 parts by weight, processability will be extremely poor. 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 possible monomers or a chlorinated product thereof, with an average degree of polymerization of about 400 to 1500 as measured by the method of JIS K6721, 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 further contain conventional plasticizers, stabilizers, ultraviolet absorbers, antioxidants,
It goes without saying that it may contain lubricants, pigments, fillers, reinforcing agents, and the like. 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 resistance, so it is highly useful as general hard products such as building materials, vehicles, agricultural and fishery materials. Next, the present invention will be explained by examples. In addition,
% and parts are based on weight. Example 1 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, dried, and the amount recovered was measured. Next, the resulting polymer was appropriately pulverized or directly passed through an 18-mesh sieve to obtain a graft copolymer under the sieve. Next, mix the ingredients shown in Table 2 in the indicated weight proportions 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. This sample's impact strength (JIS K-7111), hardness (JIS K-7202), softening temperature (according to the JIS K-6745 softening temperature test method), and weather resistance [for those with high impact strength were measured using a weatherometer. Impact strength (JIS K-7111), color tone change (visual observation), presence or absence of yoking (visual observation)] were measured. The results are shown in Table 2.

【table】

【table】

[Table] *8 Layer separation of the sheet occurred during measurement.
Example 2 50 parts of polyvinyl chloride with an average degree of polymerization of 1050, chlorine content of 67%, chlorinated polyvinyl chloride with an average degree of polymerization of 700
50 parts, graft copolymer A35 used in Example 1
methyl methacrylate with a weight average molecular weight of 600000 and 50% methyl methacrylate.
Four parts of the styrene block copolymer were mixed in the same manner as in Example 1 and pressed to obtain a sample. The results are as follows. Mixing conditions a b Normal state Impact strength (Kg・cm/cm ² ) 105 102 Hardness 110 115 Softening temperature (℃) 75 80 After 1000 hours of weathering Impact strength (Kg・cm/cm ² ) 84 89 Color change None None Chiyoking None None

Claims (1)

[Claims] 1. Vinyl chloride or a monomer mixture mainly composed of vinyl chloride (C) in the presence of an ethylene-vinyl ester copolymer or an ethylene-acrylic ester copolymer (A) and polyethylene (B) ), in which each of (A) and (B) is more than 15% by weight and the total amount of (A) and (B) is 85% by weight or less ( ) 5 to 60 parts by weight, a methyl methacrylate polymer ( ) 0.5 to 20 parts by weight, and a vinyl chloride polymer ( ) 100 parts by weight. 2 Ethylene-vinyl ester copolymer or ethylene-acrylic ester copolymer (A), polyethylene (B) and methyl methacrylate polymer ()
is obtained by polymerizing vinyl chloride or a monomer mixture (C) mainly consisting of vinyl chloride in the presence of (A) and (B) each containing 15% of the polymer portion excluding (). % by weight, and the total amount of (A) and (B) is
It consists of a graft copolymer (') and a vinyl chloride polymer () which are 85% by weight or less, and
A hard resin composition characterized in that the polymer portion in (') excluding () is 5 to 60 parts by weight, and () is 0.5 to 20 parts by weight per 100 parts by weight of ().