JP3224015B2 - Crosslinkable vinyl chloride resin composition for covering electric wires and method for producing crosslinked vinyl chloride resin for covering electric wires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a crosslinkable vinyl chloride resin composition and a method for producing the same.

[0002]

2. Description of the Related Art Vinyl chloride resin is a resin composition containing polyvinyl chloride as a base resin.
In addition, since they have excellent properties such as insulation performance, they are widely used, for example, for covering electric wires. Crosslinking is widely performed to increase the heat resistance of the vinyl chloride resin. Crosslinking methods are roughly classified into three methods: an electron beam crosslinking method, an organic peroxide method, and a silane crosslinking method.

Among them, the electron beam cross-linking method is currently the most widely used cross-linking method, which is a technique for generating cross-linking by irradiating a substance for cross-linking with a high energy beam. In addition, the resulting crosslinked resin often had defects such as discoloration. Also,
The organic peroxide method is a method in which an organic peroxide is previously mixed with a resin composition, and after molding, the mixture is heated to a decomposition temperature of the organic peroxide or more to cause a crosslinking reaction. In the case of resin, deterioration of the resin itself due to heating occurs, and thus the appearance is adversely affected or heat resistance is reduced.

On the other hand, in the silane crosslinking method, polyvinyl chloride is silane-grafted to obtain a silane-grafted vinyl chloride-based resin compound, which is mixed with a vinyl chloride-based resin composition to which a crosslinking catalyst has been added, to carry out a crosslinking reaction. This is a technique that is very inefficient. In this method, the degree of crosslinking is as low as 10%.

In order to improve the above three techniques, instead of polyvinyl chloride, a vinyl chloride monomer and an olefin monomer are copolymerized to obtain a copolymer, and this is mixed with a silane-based cross-linking agent to perform cross-linking. The technology for forming a conductive resin composition has been used, but this method also requires a manufacturing process called copolymerization, so that the efficiency is low and the product is expensive.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, that is, it does not require large-scale equipment, has a good appearance after processing, and has no reduction in heat resistance.
Another object of the present invention is to provide a crosslinkable vinyl chloride resin composition which is easy to produce.

[0007]

According to the present invention, there is provided a crosslinkable vinyl chloride resin composition for covering electric wires , comprising polyvinyl chloride, a silane compound represented by the formula 1, a free radical generator, and a silanol. It has a constitution having a condensation catalyst and a crosslinking aid or acrylonitrile-butadiene rubber.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, any polyvinyl chloride that can be used for a vinyl chloride resin can be used. In addition, a vinyl chloride copolymer can be used, but there is a disadvantage that it is expensive. The degree of polymerization is appropriately selected in consideration of the purpose of use, but it is desirable to use a linear one having a degree of polymerization of 500 or more and 3000 or less.

Wherein R represents an olefinic organic functional group, Y is a hydrolyzable organic group, and R ′ is an olefinic organic functional group and / or a hydrolyzable organic group. Examples of the silane compound shown include vinyltrialkoxysilanes such as vinyltrimethoxysilane and vinyltriethoxysilane, vinyltris (β-methoxy) silane, and vinyltriacetylsilane. Among them, vinyltrimethoxysilane and vinyltriethoxysilane are preferable because sufficient performance is obtained for the purpose of the present invention, and they are easily available and inexpensive. The amount is preferably from 0.01 to 10 parts by weight based on 100 parts by weight of the polyvinyl chloride. If the amount is less than 0.01 part by weight, the crosslinking reaction does not proceed sufficiently. On the other hand, if the amount exceeds 10 parts by weight, the effect is saturated and wasted, and the heat resistance of the crosslinked resin is rather lowered. I do.

On the other hand, the free radical generator is an organic peroxide such as dicumyl peroxide, 1,3-bis (te
(rt-butyl peroxide isopropyl) benzene, lauroyl peroxide, tert-butyl peroxide, peroxyisopropyl carbonate, tert-butyl peroctoate, diisopropyl peroxydicarbonate, benzoyl peroxide and azo compounds. Among them, dicumyl peroxide is preferable because sufficient performance is obtained for the purpose of the present invention, and it is easily available and inexpensive. The compounding amount is 0.01 part by weight or more and 1 part by weight based on 100 parts by weight of the polyvinyl chloride.
It is desirable that the content be 0 parts by weight or less. If the amount is less than 0.01 part by weight, the amount of generated radicals is too small to allow the crosslinking reaction to proceed sufficiently. On the other hand, even if it is added in an amount exceeding 10 parts by weight, the effect is saturated and wasteful. Instead, the heat resistance of the resin decreases.

Examples of the silanol condensation catalyst include metal compounds such as dibutyltin dilaurate, dibutyltin diacetate and dibutyltin dioctoate. Of these, dibutyltin dilaurate is preferred because sufficient performance is obtained for the purpose of the present invention, and it is easily available and inexpensive. The amount is preferably from 0.01 to 10 parts by weight based on 100 parts by weight of the polyvinyl chloride. 0.0
If the amount is less than 1 part by weight, the crosslinking reaction does not sufficiently proceed. On the other hand, if the amount exceeds 10 parts by weight, the effect is saturated and wasteful, and the heat resistance of the crosslinked resin is rather lowered.

Examples of the crosslinking assistant include triallyl cyanurate, diallyl phthalate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, triethylene glycol dimethacrylate, triallyl isocyanurate and the like. It is necessary that the compounding amount be 0.01 to 10 parts by weight based on 100 parts by weight of the polyvinyl chloride. If the amount is less than 0.01 part by weight, the crosslinking reaction does not proceed sufficiently. On the other hand, if the amount exceeds 10 parts by weight, the effect is saturated and wasteful, and the heat resistance of the crosslinked resin is rather lowered. I do.

Acrylonitrile-butadiene rubber can be used instead of or in combination with the crosslinking aid. The addition amount of the polyvinyl chloride is 10
When it is 0 parts by weight, it is necessary to be 0.01 part by weight or more and 100 parts by weight or less. If the amount is less than 0.01 part by weight, the crosslinking reaction does not proceed sufficiently. On the other hand, if the amount exceeds 10 parts by weight, the effect is saturated and wasteful, and the heat resistance of the crosslinked resin is rather lowered. I do.

The crosslinkable vinyl chloride resin composition of the present invention may contain a plasticizer, a stabilizer, a filler, a processing aid, an antioxidant and the like in addition to the above components. The stabilizer is added to increase the thermal stability, and a general stabilizer can be used. That is, it is a lead-based, barium-zinc-based, calcium-zinc-based, tin-based stabilizer, or the like. Here, for example, dibutyltin laurate is mentioned as a tin-based stabilizer. The amount of the stabilizer to be added is appropriately adjusted in relation to the required effect. A general amount of the stabilizer is 2% by weight or more and 10% by weight or less when the above polyvinyl chloride is 100 parts by weight. is there.

As the plasticizer, a general plasticizer for vinyl chloride resin can be used. That is, it is a phthalate-based, trimellitate-based, or polyester-based plasticizer. The addition amount of the above polyvinyl chloride is 1
It is desirable that the amount is 20 parts by weight or more and 100 parts by weight or less based on 00 parts by weight. If the amount is less than 20 parts by weight, the processability becomes poor. On the other hand, if it exceeds 100 parts by weight, the plasticizer tends to bleed or to have insufficient strength.

The filler can be appropriately selected according to the required properties and performances, and common ones include calcium carbonate, silicon dioxide, magnesium hydroxide, aluminum hydroxide, antimony (III) oxide and the like. . The amount of these additives is also adjusted according to the purpose of the addition, but is generally about 130 parts by weight or less when the above polyvinyl chloride is 100 parts by weight. As processing aids, polymethyl methacrylate, polyester processing aids and the like can be used. These addition amounts are also adjusted according to the purpose of addition.

When an antioxidant is added, those used for ordinary vinyl chloride resins can be used. The addition amount is appropriately selected, but is usually about 2 parts by weight or less when the above polyvinyl chloride is 100 parts by weight.

Since the crosslinking reaction is started by the moisture in the air after mixing the above components, if not used immediately, all the components are mixed and stored in an environment free from moisture, or For example, polyvinyl chloride, a plasticizer, a stabilizer, a filler, a processing aid or / and acrylonitrile-butadiene rubber are preliminarily mixed by a mixer to form pellets of a resin composition.
Free radical generator, silanol condensation catalyst, crosslinking aid,
When used in combination with an antioxidant, long-term storage is possible.

As described above, the crosslinkable vinyl chloride resin composition of the present invention can be obtained only by mixing the components with a high-speed mixer or the like, so that expensive and large-scale equipment such as an electron beam irradiation device is not required. Also, no discoloration due to the electron beam occurs. Further, since relatively inexpensive raw materials are used, product costs are not reduced. In addition, the crosslinking reaction proceeds only by contact with moisture in the air or by contact with water,
Since there is no particular need for heating, it is an excellent product that does not adversely affect the shape of the product due to heating.

Such a resin composition can be suitably used for all uses of a general crosslinked vinyl chloride resin. In particular, it is suitable for use for preventing a molded article which may be exposed to a high temperature condition from being deformed or deteriorated. Examples of such applications include wire coating applications such as wiring for wiring in an engine room of an automobile and wiring in a device that is heated to a high temperature, and various tubes and grommets.

[0021]

【Example】

[Examples 1 to 13] First, a resin compound was prepared. After mixing with a high-speed mixer at the mixing ratio (weight ratio) shown in Table 1, the mixture was kneaded with a pressure kneader, and extruded and granulated with a feeder ruder to form pellets. Note that diethylhexyl phthalate and trioctyl trimellitate are plasticizers, tribasic lead sulfate is a lead stabilizer, dibutyltin laurate is a tin stabilizer, trimethylolpropane trimethacrylate is a crosslinking aid, antimony oxide (III), Magnesium hydroxide and calcium carbonate are fillers.

[0022]

[Table 1]

Next, using these resin compounds, a post-addition composition was added using a high-speed mixer so as to have a weight ratio as shown in Tables 2 and 3, followed by mixing (90 ° C.) to obtain a crosslinkable resin composition. got α ~ ο. These crosslinkable resin compositions were extruded in a T-die with a 20φ extruder (extruder having a screw diameter of 20 mm) set at 190 ° C. to a thickness of 1 m.
A ribbon-shaped sheet molded product having a width of 25 mm was prepared, and this sheet was further immersed in water at 100 ° C. for 30 minutes to obtain an evaluation sample. In Table 2, vinyltrimethoxysilane and vinyltriethoxysilane are a silane compound represented by Chemical Formula 1, dicumyl peroxide and 1,3-bis (t-
Butyl peroxide isopropyl) benzene is a free radical generator, dibutyltin dilaurate and dibutyltin dioctoate are silanol condensation catalysts, and trimethylolpropane trimethacrylate and ethylene glycol dimethacrylate are crosslinking aids.

[0024]

[Table 2]

The evaluation samples composed of the crosslinkable resin compositions α to ο were evaluated for appearance, insoluble gel fraction, and heat deformation ratio. The appearance was evaluated by visual evaluation for the presence or absence of defects in the evaluation sample. The insoluble gel fraction was calculated by immersing the evaluation sample in tetrahydrofuran at 70 ° C. for 24 hours and measuring the weight of the insoluble component (insoluble gel component). The ratio of the weight of the insoluble component to the weight of the evaluation sample used was calculated. It is what I asked for. In addition, the heating deformation rate measured the thickness when a load of 2 kg was applied to the evaluation sample in the length direction in an environment of 120 ° C. for 1 hour,
The thickness deformation rate at that time is calculated.

The insoluble gel fraction is an index indicating the degree of cross-linking. If the value is low, the heat resistance is not sufficient, and it is considered that a good value is 30% or more in a general vinyl chloride resin molded product. Further, the heat deformation rate is required to be 10% or less in a general vinyl chloride resin molded product. The evaluation results at this time are also shown in Table 2.

Table 2 shows that all of the evaluation samples of Examples 1 to 13 using the crosslinkable vinyl chloride resin composition according to the present invention had good appearance, high insoluble gel fraction, and high heat deformation at the same time. You can see that. In addition, as in the above, T = 20 °
A ribbon-shaped material having a thickness of 1 mm and a width of 25 mm was obtained by extrusion through a die, and this was irradiated with an electron beam.
% And a heating deformation rate of 5%, but it was found by appearance evaluation that there was a discolored portion (Comparative Example 3).

Further, vinyltriethoxysilane was used as a silane compound in an amount of 0.1 parts by weight based on 100 parts by weight of the resin compound G.
5 parts by weight and 0.5 parts by weight of a free radical generator were added, mixed with a high-speed mixer (90 ° C.), extruded at 160 ° C., pelletized as a silane-modified copolymer, and separately added with 100 parts by weight of a resin compound G under the same conditions. Parts by weight of a catalyst masterbatch obtained by adding 2 parts by weight of dibutyltin laurate as a silanol condensation catalyst to the catalyst masterbatch.
After mixing, T-die extrusion was performed to obtain a ribbon-shaped evaluation sample (Comparative Example 4) having a thickness of 1 mm and a width of 25 mm. The evaluation sample was evaluated. The gel fraction is as low as 7% and the heating deformation ratio is 1
It was as large as 7%.

Example 14 A crosslinkable vinyl chloride resin composition was prepared at the same compounding ratio as in Example 10, and was extruded into pellets of a crosslinked master batch. The resin compound A (pellet) and the crosslinked masterbatch pellet were mixed at a weight ratio of 10: 1 and extruded by T-die at 190 ° C. to obtain a ribbon-shaped evaluation sample having a thickness of 1 mm and a width of 25 mm (Example 14). Was. The insoluble gel fraction of this evaluation sample was 61%, the heat deformation ratio was 6%, and the appearance was very good. This confirmed that the crosslinkable vinyl chloride resin composition of the present invention can be used as a crosslinked masterbatch for crosslinking various vinyl chloride resin compositions.

[Examples 15-18: Examination as a covering material for a covered electric wire] The crosslinkable resin composition α, γ, ε, θ, ξ
And ο as covering materials (covered wires 1, covered wires 2, covered wires 3, and covered wires 4, respectively) were produced. That is, these crosslinkable resin compositions have a diameter of 1.0 mm.
Was coated with a 20 mm extruder under the same conditions as those of the ribbon-shaped sheet molded products of Examples 1 to 14 to a thickness of 0.3 mm. Regarding the heat deformability of these coated electric wires, I
Heat Pressure Test of SO6722
Investigated according to. That is, these wire samples were pressed against a 0.7 mm thick edge with a load of 0.731 N, and the thickness change rate of the insulator at that time was determined. Table 3 shows the results.
In addition, the thickness change rate of the insulator of the normally covered electric wire is required to be 50% or less at an ambient temperature of 100 ° C. or more and 140 ° C. or less.

[0031]

[Table 3]

From Table 3, it can be seen that when the crosslinkable resin composition of the present invention is used for a coated electric wire, the rate of change in thickness required as a coating material is sufficiently satisfied.

[0033]

EFFECT OF THE INVENTION The crosslinkable vinyl chloride resin composition of the present invention is large due to the effects of an electron beam irradiator and the like, does not require equipment that requires cumbersome management, has a good appearance of a molded product, and has heat resistance. It is an excellent crosslinkable vinyl chloride resin composition which is easy to manufacture and does not cause a decrease in water content.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI (C08L 27/06 C08L 9:02) 9:02) C08K 5/54 (58) Investigated field (Int.Cl. ⁷ , DB name) C08L 27/06 H01B 3/30-3/46

Claims (2)

(57) [Claims] 1. A crosslinkable wire coating comprising polyvinyl chloride, a silane compound represented by the formula 1, a free radical generator, a silanol condensation catalyst, and a crosslinking aid or / and an acrylonitrile-butadiene rubber. Vinyl chloride resin composition. RR′SiY ₂ (wherein R represents an olefinic organic functional group, Y is a hydrolyzable organic group, and R ′ is an olefinic organic functional group and / or a hydrolyzable organic group. .) 2. A polyvinyl chloride for electric wire coating , comprising using polyvinyl chloride, a silane compound represented by the formula 1, a free radical generator, a silanol condensation catalyst, and a crosslinking aid or / and an acrylonitrile-butadiene rubber. A method for producing a crosslinked resin.