JPH0159293B2 - - Google Patents

Description

[Detailed description of the invention]

Flexibility of soft vinyl chloride resin can be adjusted over a wide range by adjusting the amount of plasticizer added to the resin, and it has good secondary processability, so it is often used in applications such as food packaging and medical devices. ing. However, if a molded article, sheet, film, etc. made of a vinyl chloride resin composition containing a plasticizer is left in contact with oil, body fluids such as blood, or various other aqueous solutions for a long period of time, the plasticizer may be present, albeit in a small amount. is eluted. These plasticizers used in food packaging, medical devices, etc. have generally been relatively non-toxic to living organisms, such as DOP, but it is desirable that these additives do not leach out if possible. Therefore, studies have been conducted to prevent plasticizer elution as much as possible, such as modification by surface treatment such as plasma treatment as seen in Japanese Patent Publication No. 57-6020, etc., and measures to prevent soft vinyl chloride resin from coming into direct contact with liquid. For example, in the case of a tube, the inner layer is made of a resin that does not contain a plasticizer such as urethane or EVA, and the outer layer is made of a soft vinyl chloride resin that contains a plasticizer.The method is a multilayer tube pressing method, or the addition of silicone oil. Proposals have been made for methods such as JP-A-51-88543 and the use of polyester plasticizers. Surface treatment using plasma can reduce the elution of plasticizers etc. to 1/100 to 1/1000, as stated in Japanese Patent Publication No. 57-6020, etc., but it takes a lot of man-hours, and for tubes. It has drawbacks such as inability to process long products and difficulty in secondary processing. Furthermore, the multilayer extrusion multilayer lamination method has the effect of reducing elution of plasticizer by approximately 1/3 to 1/10, although it varies depending on the resin thickness of the inner layer. However, this method also has drawbacks in terms of secondary processability and the like. On the other hand, when used in combination with a non-migratory plasticizer, such as a polyester plasticizer, a significant effect cannot be obtained unless the DOP amount is reduced to almost zero. On the other hand, silicone oils such as polymethylphenylsiloxane, polydimethylsiloxane, polymethylhydrogensiloxane, etc. described in JP-A No. 51-88543 do not have a large effect on preventing elution of plasticizers. Ta. The present invention aims to provide a vinyl chloride resin composition which does not have these drawbacks of the prior art and has a significantly improved effect of preventing elution of a plasticizer. That is, it is a soft vinyl chloride resin composition containing a plasticizer, with the general formula [In the formula, R: CH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ or a C ₁ to _{C 5} alkyl group having a carboxyl group at the end, X, Y: an integer of 1 or more, X/Y = 10 to 100
shows. ] The present invention provides a vinyl chloride resin composition containing 0.2 to 4 parts by weight of silicone oil represented by the following formula to reduce elution of a plasticizer. In the present invention, vinyl chloride resins include polyvinyl chloride resins, copolymers of vinyl chloride and vinyl compounds such as vinyl acetate, and blend resins mainly composed of vinyl chloride resins and resins such as ABS, MBS, and MMA. This includes: Examples of plasticizers include phthalate esters such as DOP, adipate esters, citric acid esters, and plasticizers used for plasticizing vinyl chloride resins such as epoxidized soybean oil. The silicone used in the present invention has the general formula [In the formula, R: CH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ or a C ₁ to _{C 5} alkyl group having a carboxyl group at the end, X, Y: an integer of 1 or more, X/Y = 10 to
Shows 100. ] In which R is modified with an amino group or a carboxyl group, and each is individually grafted onto polydimethylsiloxane. Furthermore, the same effect can be obtained even if polydimethylsiloxane modified with amino groups and carboxyl groups is mixed and grafted onto polydimethylsiloxane. This carboxyl-modified polydimethylsiloxane or amino-modified polydimethylsiloxane is added in an amount of 0.2 to 4 parts by weight, preferably 0.5 to 2 parts by weight, per 100 parts by weight of the vinyl chloride resin. If the amount added is small, the effect of preventing plasticizer elution will be small, while if the amount added is large, the lubricity of silicone will be strong, making it difficult to mix with the vinyl chloride resin, resulting in processing problems. Generally, if the amount of plasticizer added increases, the amount of silicone added tends to increase as well. The resulting product has a silicone content of 0.2 in terms of transparency.
It is translucent at about parts by weight, and becomes opaque when added in large amounts, but it has less tackiness characteristic of soft vinyl chloride resins, and the amount of plasticizer eluted is 1/5.
Since it can be reduced to ~1/20, it can be used in medical devices, food packaging, and other applications where plasticizer elution is a problem. Example A vinyl chloride resin and additives were mixed and rolled according to the formulation shown in Table 1, and the mixture was press-molded into a 1 m/m sheet. The numerical values in the table indicate parts by weight when the resin is taken as 100.

[Table] The carboxyl-modified polydimethylsiloxane used here has the general formula described above, where R is C ₂ H ₄ COOH,
X=98, Y=2, and amino-modified polydimethylsiloxane has R
CH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ , X=98, Y=2
I used the one from The former is used to improve the lubricity of vinyl acetate and acrylic acid ester resins, and the latter is used to improve mold release properties of urethane resins. There are no examples, and nothing is known about the effect of preventing plasticizer elution. Next, these samples were cut into disk shapes, placed in a stainless steel cup filled with distilled water so that only one side was in contact with the liquid, and heated at 40°C with a shaking width of 6 cm and cycled.
After shaking at 200 times/min for 6 hours, the test solution was subjected to gas chromatography to detect the eluted DOP.
The amount was measured. Table 2 shows the results of the elution DOP of the obtained sheet.

[Table] As mentioned above, the amount of eluted DOP is surprisingly 1/5 to 1/20 compared to the one with ordinary plasticizer added.
I was able to make it even less. As described above, the vinyl chloride resin product according to the present invention can significantly reduce the elution of plasticizer, and is therefore useful in the medical field, food packaging field, and other industrial fields.

Claims (1)

[Scope of Claims] 1. A soft vinyl chloride resin composition containing a plasticizer, which has the general formula: [In the formula, R: CH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ or a C ₁ to _{C 5} alkyl group having a carboxyl group at the end, X, Y: an integer of 1 or more, X/Y = 10 to 100
shows. ] A vinyl chloride resin composition characterized by containing 0.2 to 4 parts by weight of a silicone oil represented by the following formula to reduce elution of a plasticizer.