JPS6261223B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyvinyl chloride foam resin composition that has good shape retention at high temperatures, foams to a similar shape when foamed, has high elasticity, and has good creep resistance. Generally, by adding a plasticizer to vinyl chloride resin, a composition having a soft, rubber-like feel, a so-called soft vinyl chloride resin composition, can be obtained. It is well known that a soft vinyl chloride foam resin composition can be obtained by adding a foaming agent such as azodicarbonamide to this composition. However, these foamed resin compositions generally have a low expansion ratio, and the expansion ratio is limited to 1 to 2 times.
The reason why only a low foaming ratio can be obtained is that the viscosity of the soft vinyl chloride resin is too low at the temperature at which the foaming agent decomposes and generates gas, making it difficult to form uniform foam cells. It is caused by For this purpose, various studies have been conducted to obtain a high expansion ratio, but in addition to paste foaming that can be foamed at low temperatures and crosslinking foaming that can be foamed by crosslinking, there are still good high foaming soft vinyl chloride resin compositions. has not been obtained. However, paste foaming, which allows for high foaming, has problems with creep resistance, shape retention at high temperatures, rebound resilience, etc., while crosslinking foaming has problems with rubber elasticity,
There was a problem with the coloring etc. As described above, it is an important issue to create a soft vinyl chloride resin foam with improved creep resistance, shape retention at high temperatures, rebound resilience, etc., and has been widely requested by the industry. It was hot. Under these circumstances, the inventors of the present invention conducted intensive studies and found that polyvinyl chloride resin 100
Part by weight and nitrile rubber (hereinafter abbreviated as NBR) gel content insoluble in methyl ethyl ketone 20-95% by weight
A vinyl chloride copolymer having active hydrogen in the molecule, a thermoplastic polyurethane, and a crosslinking agent are blended into a composition consisting of 10 to 400 parts by weight of nitrile rubber, the remainder of which is soluble in methyl ethyl ketone, and 25 to 300 parts by weight of a plasticizer. By adding 5 to 60 parts by weight of a resin composition (hereinafter abbreviated as composition Q) and 1 to 50 parts by weight of a blowing agent such as azodicarbonamide, it is possible to create foams that cannot be obtained with conventional flexible vinyl chloride resin foams. A polyvinyl chloride foam resin composition with a foaming ratio of 5 to 30 times, good shape retention at high temperatures, foams to a similar shape when foamed, high elasticity, and improved creep resistance. I was able to obtain this. That is, by adding 5 to 60 parts by weight of Composition Q, crosslinking will proceed only with Composition Q during foaming, and cells in the foamed resin will be formed finely and uniformly, resulting in elasticity and shape retention, especially at high temperatures. The present invention provides a composition having a good and high expansion ratio. Furthermore, by adding an acrylonitrile copolymer and a methyl methacrylate copolymer to the composition Q, the compatibility between the thermoplastic polyurethane and the vinyl chloride polymer can be improved. The thermoplastic polyurethane used in the present invention is a linear polyurethane consisting of a bifunctional polyol and a diisocyanate, having a hydroxyl group at the molecular end, and capable of reacting with a crosslinking agent. The object of the present invention is to provide a polyvinyl chloride foam resin composition that exhibits good properties such as creep resistance, shape retention at high temperatures, and impact resilience, and provides a high expansion ratio of about 5 to 30 times. That is, the present invention uses polyvinyl chloride resin 100
10-400 parts by weight of NBR, 20-95% by weight of NBR gel insoluble in methyl ethyl ketone (hereinafter abbreviated as MEK) and the balance soluble in MEK, 5-60 parts by weight of Composition Q, and 25-300 parts by weight of plasticizer. This is a vinyl chloride resin composition whose main components are 1 to 50 parts by weight of foaming agent and 1 to 50 parts by weight of a blowing agent. As used herein, the term "gel fraction insoluble in MEK" refers to the amount of gel that is insoluble in MEK at a temperature of 25°C.
It refers to the extraction residue that is extracted for 16 hours and separated using a 100 mesh filter. In addition, for vinyl chloride copolymerization having active hydrogen in the molecule, a vinyl chloride monomer and a monomer having active hydrogen such as a hydroxyl group or a carboxyl group in the molecule can be polymerized using the usual suspension polymerization method, bulk polymerization method, or solution polymerization method. Examples of products that can be obtained through legal copolymerization include:
Examples include vinyl chloride-hydroxyethyl acrylate copolymer, vinyl chloride-monobutyl fumarate copolymer, and partially saponified vinyl chloride-vinyl acetate copolymer. Examples of crosslinking agents include vinyl chloride copolymers with active hydrogen in the molecule and compounds with two or more functional groups in the molecule that can react with thermoplastic polyurethane resins, such as isocyanate groups and carboxyl groups in the molecule. Examples include compounds having a group, a hydroxyl group, etc., dibasic acid anhydrides, and a typical example is a phenol-blocked melimethylolpropane tolylene diisocyanate adduct. The characteristics of the present invention are that 100 parts by weight of polyvinyl chloride resin, 10 to 400 parts by weight of NBR consisting of 20 to 95% by weight of NBR gel insoluble in MEK, and the balance soluble in MEK, 5 to 60 parts by weight of composition Q, and plasticizer. It is a vinyl chloride foaming fat composition whose main components are 25 to 300 parts by weight of a foaming agent and 1 to 50 parts by weight of a blowing agent.The polychlorinated vinyl resin and NBR added in large amounts are vulcanized like ordinary rubber Alternatively, in order to crosslink only a small amount of Composition Q without crosslinking, the foaming ratio is 5, which has good creep resistance, shape retention at high temperatures, impact resilience, etc.
It has now become possible to obtain foams that are approximately 30 times more foamed. That is, it is a special feature that a highly foamed body having an expansion ratio of about 5 to 30 times can be obtained as a thermoplastic resin composition. The reason why highly foamed products were made possible is that the composition of the present application has very good shape retention properties at high temperatures. Almost no deterioration can be seen. For this reason, when foaming is performed, a highly foamed product with a shape similar to the shape before foaming can be obtained. At this time, there was hardly any collapse of the foam cells or melting of the molded product, which is seen in ordinary foams. That is, it was confirmed that a good highly foamed product could be obtained using various molding methods in the range specified in the claims of the present application. The specific molding method will be explained in Examples. Despite the excellent properties mentioned above, unlike vulcanized rubber, it is a thermoplastic resin composition that can be recycled during molding, and can be used with thermoplastic resins such as injection molding machines, extrusion molding machines, and blow molding. Machines, calendar molding machines, and press molding machines can be used. In order to obtain a highly foamed product, NBR10-400 is made of 100 parts by weight of polyvinyl chloride resin, 20-95% by weight of NBR gel insoluble in MEK, and the balance soluble in MEK.
Composition Q is characterized by consisting of at least five components: 5 to 60 parts by weight, 25 to 300 parts by weight of a plasticizer, and 1 to 50 parts by weight of a blowing agent.
Even if it is not satisfied, the processability is good and the foaming ratio is 5.
~30x composition is not obtained. Similarly, in order to obtain a good foam, when using NBR with a gel content insoluble in MEK of less than 20% by weight, it is impossible to increase the foaming ratio from 5 to 30 times. Ta. In order to increase the expansion ratio from 5 to 30 times, as claimed in the patent, NBR with a gel content insoluble in MEK of 20% to 95% by weight was effective, but a particularly good range was , 40% by weight of gel insoluble in MEK
This was the case when 90% by weight or less of NBR was used. Regarding the amount of NBR added, if it is less than 10 parts by weight, it will have no effect at all, and if it exceeds 400 parts by weight, the properties of the polyvinyl chloride resin composition will be lost and problems will occur in moldability, aging properties, etc. It was undesirable. A particularly desirable range is 50 to 200 parts by weight, as a highly foamed composition having good creep resistance, shape retention at high temperatures, and processability was obtained. Also
There was no significant difference in the amount of acrylonitrile added in NBR or the viscosity. Regarding the plasticizer, if it is less than 25 parts by weight, foaming will be uneven, and if it exceeds 300 parts by weight, productivity and processability will be poor and it will be difficult to foam into similar shapes during foaming, resulting in good foaming in either case. I couldn't get a body. As a particularly desirable range, a good foam could be obtained in a range of 40 to 200 parts by weight. Examples of such plasticizers include alkyl esters of aromatic polybasic acids such as dibutyl phthalate, dioctyl phthalate, butylbenzyl phthalate, alkyl esters of aliphatic polybasic acids such as dioctyl sebacate, and tricresyl phosphate. There was almost no difference in foaming state, magnification, and processability among all the plasticizers. As for the foaming agent, good foams could be obtained within the range of 1 to 50 parts by weight. Examples of such blowing agents include azodicarbonamide, barium azodicarboxylate,
4,4'-oxybisbenzenesulfonyl semicarbezide, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, N,N'-dinitrosopentamethylenetetramine, hydrazodicarbonamide, P-toluene Sulfonyl hydrazide, benzene-1,3-disulfonyl hydrazide, diphenylsulfone-3,3'-disulfonyl hydrazide, P-toluenesulfonyl semicarbazide, 4,4'-oxybisbenzenesulfonyl Examples include hydrazide, trihydrazinotriazine, etc., and are used as appropriate within the above range. The polyvinyl chloride resin used in the present invention includes the following copolymers. That is, monomers copolymerizable with vinyl chloride include fatty acid vinyl esters, vinylidene halides, acrylic acid alkyl esters, methacrylic acid alkyl esters, acrylonitrile, alkyl vinyl ethers, styrene, and derivatives thereof. The vinyl chloride resin composition of the present invention can be used as is, but if necessary, other thermoplastic resins,
It is used by blending rubber, heat stabilizers, fillers, pigments, processing aids, etc. Other thermoplastic resins include ethylene-vinyl acetate copolymer, chlorinated polyethylene, ABS resin, AS resin, urethane acrylic resin, etc. Rubbers other than those used in the present invention include
NBR, CR, etc. are used. Examples of heat stabilizers include lead-based heat stabilizers such as tribasic lead sulfate, tin-based stabilizers such as dibutyltin malate, and metal soaps such as zinc stearate and calcium stearate. It is generally used in an amount of 20 parts by weight or less, and can be used as required. Examples of the filler include carbon black, calcium carbonate, titanium oxide, talc, asbestos, aluminum hydroxide, magnesium hydroxide, etc., which can be used as required, and the amount used is not limited. Examples of the pigment include color carbon black, chrome yellow, titanium oxide, and phthalocyanine green, which can be used depending on the purpose. As processing aids, those commonly used for vinyl chloride resins, such as low molecular weight polyethylene and higher fatty acid esters, are used. The vinyl chloride resin composition based on the present invention can be granulated. That is, it is mixed with a plasticizer, a stabilizer, etc. using a mixer such as a super mixer or a blender, and then kneaded and granulated using a Banbury mixer, mixing roll, extruder, etc. The granulated pellets could be molded into highly foamed products by injection molding, extrusion molding, press molding, blow molding, calendar molding, etc., and had good processability. The vinyl chloride foam resin composition according to the present invention is
Taking advantage of its creep resistance and shape retention at high temperatures, it is used for applications such as insulation materials, cushion materials, foam tubes, foam sheets, packing, grommets, and sealing materials. In addition, by adding NBR, it goes without saying that the oil resistance unique to NBR can be imparted, as well as the heat aging resistance unique to polyvinyl chloride resins, creep resistance, shape retention at high temperatures, and oil resistance. ,
It can be said that it is a vinyl chloride thermoplastic resin foam that can satisfy heat aging resistance. Utilizing this excellent property for purposes other than the above,
It is expected that it will be widely used. The technical contents of the present invention will be explained using specific examples. Example 1 100 parts by weight of vinyl chloride resin with an average degree of polymerization of 2600, 100 parts by weight of 2-ethylhexyl phthalate,
A composition consisting of 12 parts by weight of the blowing agent azodicarbonamide, 5 parts by weight of tribasic lead sulfate, 1 part by weight of stearic acid, and 30 parts by weight of Composition Q has a gel content of 70% by weight that is insoluble in MEK, and the remainder is soluble in MEK. Soluble NBR (acrylic nitrile content 35% by weight), in order to compare the effect of the present invention, the gel content insoluble in MEK was 0.2% by weight.
NBR (acrylonitrile content 35% by weight), the balance of which was soluble in MEK, was added as shown in Table 1, respectively.

【table】

[Table] Example 2 Based on experiment number 6 of Example 1, the amount of NBR added was 100 parts by weight, and the MEK-insoluble gel content of NBR was changed as shown in Table 2, and the same as Example 1 was prepared. The evaluation was carried out using the method. As can be seen from Table 2, NBR with a gel content of less than 20% by weight did not give good results in terms of shape retention, and those with a gel content of more than 95% by weight had poor moldability and could not be processed. Especially the gel content is 50
Good results were obtained at ~90% by weight.

[Table] Example 3 In Example 1, Experiment No. 6, the amount of 2-ethylhexyl phthalate added was varied as shown in Table 3, and evaluation was performed in the same manner as in Example 1. As can be seen from the results in Table 3, when the amount of 2-ethylhexyl phthalate added was less than 10 parts by weight or exceeded 300 parts by weight, processability was poor and there were problems in actual handling. In particular, when the amount of 2-ethylhexyl phthalate added was in the range of 40 to 200 parts by weight, the expansion ratio and shape retention were good.

【table】

[Table] Example 4 In Example 1, Experiment No. 6, evaluation was performed in the same manner as in Example 1, except that the type of plasticizer was changed as shown in Table 4. The number of parts of plasticizer added is 100.
Parts by weight. As is clear from Table 4, even if the type of plasticizer is changed, the extrusion processability, expansion ratio, and shape retention are good.

[Table] Example 5 In Example 1, Experiment No. 6, the amount of Composition Q was varied and evaluation was performed in the same manner as in Example 1.
As can be seen from Table 5, if the amount is less than 5 parts by weight, the effect on shape retention is weak, if it exceeds 100 parts by weight, the processability is poor, and if it is 30 parts by weight, good results were obtained.

【table】

Claims (1)

[Scope of Claims] 1 A: 100 parts by weight of polyvinyl chloride resin, B: 10-400 parts by weight of nitrile rubber consisting of 20-95% by weight of nitrile rubber gel insoluble in methyl ethyl ketone, and the remainder soluble in methyl ethyl ketone, C: Inside the molecule 5 to 60 parts by weight of a resin composition containing a vinyl chloride copolymer having active hydrogen, a thermoplastic urethane, and a crosslinking agent, D 25 to 300 parts by weight of a plasticizer, and E 1 to 50 parts by weight of a blowing agent. A vinyl chloride foam resin composition as an ingredient.