JPH0152416B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION This invention relates to polymer compositions. More specifically, the present invention relates to a polymer composition related to a vinyl acetate polymer such as an ethylene-vinyl acetate-carbon monoxide copolymer, which has improved processability, odor, thermal stability, and the like. Generally, ethylene polymers are nonpolar, so
It has the disadvantage of poor compatibility with other polymers. However, since ethylene-vinyl acetate-carbon monoxide copolymer has a highly polar carbon monoxide unit in its molecule, it is incompatible with many polymers containing polar groups, such as polyvinyl chloride, polyamide, and cellulose derivatives. It is characterized by excellent compatibility (Japanese Patent Publication No. 55-50063). In particular, ethylene-vinyl acetate-carbon monoxide copolymer (hereinafter sometimes abbreviated as carbon monoxide copolymer) is a permanent plasticizer for vinyl chloride resins, instead of conventional liquid plasticizers. It is used as an agent or modifier. The use of such a carbon monoxide copolymer as a permanent plasticizer is one of the applications that makes the most of its characteristics, and it eliminates the volatilization and extraction of liquid plasticizers, which have been the drawbacks of conventional vinyl chloride resin formulations. There is no change in the rigidity of the resin compound over time, or contamination of other base materials due to migration of the liquid plasticizer. Therefore, sheets molded from vinyl chloride resin compositions containing carbon monoxide copolymers are used as water-stop sheets for industrial wastewater reservoirs that require outdoor durability, and are required to have a high degree of non-migration. It is also used in fields where conventional vinyl chloride resin formulations are not satisfactory, such as cover sheets for electrical products. However, this carbon monoxide copolymer or its blend with other synthetic resins such as vinyl chloride resins cannot be heated to high temperatures during kneading or molding, or cross-linked with organic peroxides or electron beam irradiation. When the reaction is carried out, disadvantages such as relatively poor thermal stability and a pungent odor are observed in the product. These drawbacks are common to vinyl acetate-based polymers, but especially in this carbon monoxide copolymer, the vinyl acetate unit has high reactivity because it is adjacent to the carbon monoxide unit, and it can be used at lower temperatures. It has a tendency to release acetic acid and has a remarkable tendency to impart a pungent odor to the product. Therefore, it is generally known to add magnesium oxide to improve these drawbacks. However, although the addition of magnesium oxide is certainly effective in preventing the production of irritating odors in the product, it may impair release properties from the roll surface during processing or impair thermal stability. or For example, heating at 120℃ for 400 hours, which is used to evaluate the thermal stability of vehicle seats, etc.
Sheets to which magnesium oxide is added have problems such as increased loss on heating and accelerated discoloration. Among these problems, poor releasability from the roll surface is particularly fatal, and processing operations cannot be carried out smoothly, causing serious problems in the kneading and molding process. As described above, the above-mentioned problems have been an obstacle to the practical use of carbon monoxide copolymers or blends of them with other synthetic resins, and therefore, the processing of carbon monoxide copolymers has There was a strong desire to improve properties such as properties, odor, and thermal stability. The inventor is
As a result of intensive research aimed at solving these problems, it has been discovered that a polymer composition to which a specific epoxy compound is added can effectively solve the above problems. Also,
It has been found that the solution of the present invention can be similarly effectively applied to deodorizing and improving thermal stability of vinyl acetate polymers other than carbon monoxide copolymers. Therefore, the present invention relates to a polymer composition, which comprises a vinyl acetate polymer and a nitrogen-containing or alicyclic epoxy compound; It consists of other synthetic resins and nitrogen-containing or alicyclic epoxy compounds that are compatible with the coalescence. Examples of vinyl acetate polymers include polyvinyl acetate, ethylene-vinyl acetate polymers and their vinyl chloride graft copolymers, ethylene-vinyl acetate-carbon monoxide copolymers, vinyl chloride-vinyl acetate polymers, etc. are used, and in the following description, as a representative example, the case of ethylene-vinyl acetate-carbon monoxide copolymer, which is most sought after to solve the above problems, will be explained. The ethylene-vinyl acetate-carbon monoxide copolymer used in the present invention has ethylene by weight.
40-80%, preferably about 60-70%, vinyl acetate about 15-60%, preferably about 20-35%, and carbon monoxide about 5-30%, preferably about 5-15%. It is possible to further copolymerize other monomers as necessary. Details of the method for producing such a carbon monoxide copolymer are described, for example, in Japanese Patent Publication No. 50063/1983. Specific epoxy compounds used include nitrogen-containing epoxy compounds typified by glycidylamine type epoxy compounds such as triglycidyl isocyanurate, tetraglycidyl metaxylene diamine, and tetraglycidyl diaminodiphenylmethane, or vinylcyclohexene diepoxide; At least one type of alicyclic epoxy compound such as 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate is used, and nitrogen-containing epoxy compounds are particularly preferably used. These epoxy compounds are used in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the carbon monoxide copolymer.
It is used in a proportion of 0.5 to 5 parts by weight. If the epoxy compound is used in a proportion smaller than this, the desired effect in preventing irritating odors will not be obtained, while if the proportion is greater than this, the melt viscosity of the polymer composition will decrease during melt-kneading. It becomes sticky and the moldability is impaired. When using other epoxy compounds, such as glycidyl ether type epoxy compounds such as bisphenol A diglycidyl ether, glycidyl ester type epoxy compounds such as phthalic acid diglycidyl ester, and linear aliphatic epoxy compounds such as epoxidized soybean oil, etc. However, the purpose of the present invention cannot be achieved due to insufficient removal of irritating odors. Carbon monoxide copolymers are blended with other synthetic resins that are compatible with them, such as halogenated polymers, polyamides, cellulose derivatives, etc., especially vinyl chloride resins, and used as permanent plasticizers for these synthetic resins. However, even if a specific epoxy compound is added to such a compound, the polymer composition prepared therein will not have the same additive effect. It will be done. Vinyl chloride resins include not only vinyl chloride homopolymers, but also vinyl chloride and other comonomers,
For example, α-olefins such as ethylene and propylene, vinyl esters such as vinyl acetate, unsaturated carboxylic acid esters such as acrylic esters, vinyl ethers such as alkyl vinyl ethers, and other halogens such as vinyl bromide and vinyl fluoride. Vinyl compounds, styrene, acrylonitrile,
Other vinyl compounds such as vinylidene chloride or copolymers with vinylidene compounds are used, and if necessary, these vinyl chloride resins may be blended with a liquid plasticizer. The polymer composition is prepared by dry blending or melt blending the components described above simultaneously or sequentially. In the case of dry blending, in a roll, extruder, etc.
At the stage when the carbon monoxide copolymer or the other synthetic resin is melt-plasticized, a specific epoxy compound is also easily and uniformly melt-mixed at the same time. In the case of melt blending, single screw extruder, twin screw extruder,
It is sufficient to melt and mix using various mixer rolls such as Banbury mixer, kneader, etc.
There is no particular restriction on the mixing order among them. A polymer composition prepared by adding a specific epoxy compound to a carbon monoxide copolymer or a blend of it and other synthetic resins has the following effects. (1) As mentioned above, in the case of a polymer composition prepared by adding magnesium oxide, the releasability from the roll surface during kneading and molding is poor, but the polymer composition according to the present invention has good release properties from the roll surface. It shows good releasability from the roll surface. (2) As mentioned earlier, molded products made from carbon monoxide copolymers or their blends with other synthetic resins, such as films and sheets, have a pungent odor. This is thought to be due to acetic acid generated by thermal decomposition of vinyl acetate units in the carbon monoxide copolymer when heated to high temperatures such as during molding. However,
It is presumed that in the polymer composition according to the present invention, this acetic acid is captured as an acetate ester through a ring-opening reaction of a specific epoxy compound, and therefore the product does not have an irritating odor. (3) As mentioned above, in the case of a polymer composition prepared by adding magnesium oxide, the aging properties of the product are significantly impaired, the discoloration of the product is accelerated, and the weight loss is also large. In contrast, in the polymer composition according to the present invention, the aging properties of the product are not impaired by the addition of a specific epoxy compound. As described above, the polymer composition according to the present invention does not exhibit any particular side effects due to the addition of a specific epoxy compound, and can improve mold release properties and stimulate products, which are required from a practical standpoint. It must be noted that it has outstanding effects in preventing odor and improving aging characteristics. Furthermore, vinyl acetate polymers or resin compositions of them and other synthetic resins are crosslinked using organic peroxides or electron beam irradiation to improve their mechanical properties and blocking properties such as stickiness at high temperatures. Although this is generally done, the addition of an epoxy compound also effectively acts to trap acetic acid liberated during these crosslinking reactions. Next, the effects of the present invention will be explained with reference to Examples. Examples 1 to 6 Polymer compositions having the following formulations were prepared,
Then, a sheet was formed, and measurements and evaluations regarding the items described below were performed. Polyvinyl chloride (average degree of polymerization 1000) 100 parts by weight Carbon monoxide copolymer (vinyl acetate 24%, carbon monoxide 10%, MI35dg/min) 100 Ba-Zn stabilizer 2.5 Phosphite 0.5 Epoxidized soybean oil 5 Phenol antioxidant 0.3 Specific epoxy compound Specified amount [Measurement and evaluation items] Roll releasability: 165℃ using a 6-inch roll
Stimulating odor: 5 g of the above sheet was sealed in a 200 ml glass bottle, heated at 100°C for 4 hours, then opened, and the stinging odor was measured. Discoloration (△E): The degree of discoloration of the above sheet heated at 120℃ for one week was investigated using a color difference meter (Suga Test Instruments KK Color Computer Model SM-2).Heating loss: At 120℃ Comparative Example 1 In which the change in weight of the sheet was examined after heating for 400 hours In Examples 1 to 6, no epoxy compound was used. Comparative Example 2 In Examples 1 to 6, 1 part by weight of magnesium oxide was used instead of the epoxy compound. Comparative Example 3 In Examples 1 to 6, hisphenol A diglycidyl ether (Mitsui Petrochemicals Epomic R-301) was used instead of the specific epoxy compound.
Parts by weight were used. The measurement and evaluation results obtained in Examples 1 to 6 and Comparative Examples 1 to 3 above are shown in the following table.

[Table] Example 7 Ethylene-vinyl acetate polymer (vinyl acetate content 19% by weight, melt index 2.5dg/min)
After kneading 100 parts by weight and 2 parts by weight of triglycidyl isocyanurate with a roll at 90°C for 10 minutes to prepare a uniform polymer composition, a sheet with a thickness of 0.4 mm was prepared using a hot press at 140°C. Molded. Next, this sheet is processed using an electron beam accelerated irradiation device.
It was irradiated with an electron beam of 10 megarads. The obtained electron beam irradiated sheet has no irritating odor due to free acetic acid and has a gel fraction (24
The percentage of undissolved portion after time extraction was 72%.
The blocking properties of the sheet have been improved. Comparative Example 4 An electron beam irradiation sheet was produced in Example 7 without using triglycidyl isocyanurate. This sheet had a strong pungent odor due to free acetic acid, and its gel fraction was 70%.

Claims (1)

[Scope of Claims] 1. A polymer composition comprising 100 parts by weight of a vinyl acetate polymer and 0.1 to 10 parts by weight of a nitrogen-containing or alicyclic epoxy compound. 2. Claim 1, wherein the vinyl acetate polymer is an ethylene-vinyl acetate-carbon monoxide copolymer.
The polymer composition described in . 3. A polymer composition comprising 100 parts by weight of a vinyl acetate polymer, another synthetic resin compatible with the vinyl acetate polymer, and 0.1 to 10 parts by weight of a nitrogen-containing or alicyclic epoxy compound. 4. Claim 3, wherein the vinyl acetate polymer is an ethylene-vinyl acetate-carbon monoxide copolymer.
The polymer composition described in . 5. The polymer composition according to claim 3, wherein the other synthetic resin is a vinyl chloride resin.