JPH07258496A - Cross-linkable resin composition and cross-linked molded article - Google Patents

Abstract

PURPOSE:To provide a crosss-linkable resin composition containing a fluorine- containing resin, a silane-modified olefin polymer and a specific modified polymer at specific ratios and giving a cross-linked molded article having flexibility and excellent solvent resistance. CONSTITUTION:This resin composition contains (A) 100 pts.wt. of a fluorine- containing resin such as polyvinyl fluoride and polyvinylidene fluoride, (B) 5-300 pts.wt. of a silane-modified olefin resin such as a silane-modified ethylene- vinyl acetate copolymer and a silane-modified ethylene-methyl (meth)acrylate copolymer and (C) 5-50 pts.wt. of a modified polymer produced by subjecting an olefin polymer and vinyl acetate monomer or an alkyl alkylate monomer to graft-reaction condition. A cross-linked material can be produced by exposing the composition with steam in the presence of a silanol condensation catalyst to effect the cross-linking of the product.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a fluorine-containing resin, a silane-modified olefin polymer, and a modification obtained by subjecting an olefin polymer and a vinyl acetate monomer or an alkyl alkylate monomer to a graft reaction condition. The present invention relates to a crosslinkable resin composition containing a polymer, and a crosslinked molded article formed from the composition.

[0002]

2. Description of the Related Art Fluorine-containing resins generally have excellent solvent resistance, no water absorption, and excellent weather resistance, heat resistance, abrasion resistance, non-adhesiveness and the like. For example, polytetrafluoroethylene (PTFE) is a typical fluorine-containing resin, and has excellent heat resistance, and is therefore used as a material for coating the inner surface of chemical equipment piping, a material for packing, and the like. Due to its excellent lubricity, it is widely used as oil-free bearings and sliding materials.

However, since PTFE has a high melting point and is difficult to be melted by heating, it has poor moldability and has a drawback that it must be molded by a sintering molding method. for that reason,
Fluorine-containing unsaturated monomers other than tetrafluoroethylene, copolymers with tetrafluoroethylene using other unsaturated monomers, or fluorine-containing resins that do not use tetrafluoroethylene improve the moldability of PTFE. It has become possible to obtain improved thermoplastic resins having the characteristics of PTFE. However, although these fluorine-containing resins are excellent in the above-mentioned properties, they are expensive, and it is considered that the combination with an inexpensive material is useful for general purposes. Polyalkylmethacrylates are known as materials compatible with fluorine-containing resins, but composite materials are poor in flexibility, so for applications such as coating materials and tubes that require flexibility It wasn't enough.

On the other hand, as an attempt to compound a fluorine-containing resin, a fluorine-containing resin composition containing a modified ethylene polymer grafted with a specific vinyl acetate or acrylic alkylate, which is compatible with the resin, has been proposed. (Japanese Patent Publication No. 4-20940, Japanese Patent Publication No. 4-73459). However, since these modified ethylene polymers have high polarity, there is a problem that the compounded one has a lower solvent resistance than the fluorine-containing resin alone.

[0005]

The inventor of the present invention has conducted extensive studies for the purpose of improving the above-mentioned drawbacks, and as a result,
The present invention has been completed based on the finding that a crosslinkable fluorine-containing resin composition obtained by mixing a specific modified polyolefin with a fluorine-containing resin has excellent solvent resistance and a crosslinked molded article having flexibility can be obtained. It is a thing. That is, according to the present invention, (a) 100 parts by weight of fluorine-containing resin (b) Silane-modified olefin polymer 5
300 parts by weight, and (c) 5 to 50 parts by weight of a modified polymer obtained by subjecting an olefin polymer and a vinyl acetate monomer or an alkyl alkylate monomer to a graft reaction condition. And a crosslinked molded article obtained by exposing the crosslinkable resin composition to a crosslink by exposing it to a water atmosphere in the presence of a silanol condensation catalyst.

[Detailed Description of the Invention] (1) Fluorine-Containing Resin Examples of the fluorine-containing resin used in the present invention include polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, and ethylene-tetrafluoroethylene copolymer. , Ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and other commercially available products are appropriately used. Among them, polyvinyl fluoride and polyvinylidene fluoride are preferable. Further, it is also possible to blend and use another polymer that is compatible with the fluorine-containing resin, and as an example, a blend of polyvinylidene fluoride and polymethylmethacrylate is known. Of course, it is also possible to add various plasticizers, stabilizers, inorganic filler additives, pigments and the like which are usually added.

(2) Silane-modified olefin polymer The silane-modified olefin polymer used in the present invention is an olefin polymer containing an alkoxysilane group in the molecule, and the polymers are crosslinked by the alkoxysilane group. It is a thing. A preferred example of the silane-modified olefin polymer is an olefin polymer modified with an alkoxysilane group-containing vinyl compound. Specifically, vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane is graft-copolymerized with an olefin polymer, or an alkoxysilane group-containing vinyl compound and ethylene are randomly copolymerized. . Regarding these silane-modified olefin polymers, for example, JP-B-48-1711, JP-A-59-36115 and JP-A-55-96.
It is described in detail in Publication No. 11 and is available on the market.

The olefin polymer used here is ethylene, propylene, butene-1, pentene-.
1, a homo- or copolymer of an olefin having about 2 to 20 carbon atoms such as hexene-1, or a copolymer of a majority weight of these olefins and a copolymerizable vinyl monomer. Examples of the copolymerizable vinyl monomer include vinyl esters such as vinyl acetate; unsaturated organic acids such as acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, maleic anhydride, and itaconic acid (these (Including esters, salts, and anhydrides thereof) and the like. The term "copolymer" as used herein includes random, block and graft copolymers. Further, two or more kinds of these olefin polymers may be used in combination. Preferred examples of these silane-modified olefin polymers include:
Since the compatibility and flexibility with the fluorine-containing resin is good, silane-modified ethylene-vinyl acetate copolymer, silane-modified ethylene-methyl acrylate copolymer, silane-modified ethylene-methyl methacrylate copolymer Can be mentioned.

(3) Modified Polymer The modified polymer constituting one component of the composition of the present invention is obtained by subjecting an olefin polymer and a vinyl acetate monomer or an alkyl acrylate monomer to a graft reaction condition. Is what you get. 1) Raw Materials (a) Olefin Polymer As the olefin polymer that can be used in the present invention, ethylene, propylene, butene-1, pentene-1, hexene-1, etc., having an olefin having about 2 to 20 carbon atoms, alone or as a copolymer. Examples thereof include a combination, or a copolymer of a majority weight of these olefins and a copolymerizable vinyl monomer. Examples of the copolymerizable vinyl monomer include vinyl esters such as vinyl acetate; unsaturated organic acids such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, glycidyl methacrylate, maleic anhydride, and itaconic acid; Its derivatives (their esters, salts,
(Including anhydride) and the like. The copolymers referred to herein include random, block and graft copolymers. Further, these olefin polymers may be used as a mixture of two or more kinds.

(B) Vinyl Acetate Monomer or Alkyl Acrylate Monomer Vinyl acetate monomer or alkyl acrylate (both monomers are referred to as "vinyl monomer" hereinafter) used in the production of the modified polymer. In some cases, a commercially available product can be used. Specific examples of the alkyl acrylate monomer include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, glycidyl methacrylate and the like. Further, not only these vinyl acetate monomers and alkyl acrylate monomers, but also a mixture of a majority of these vinyl monomers with other vinyl monomers copolymerizable therewith may be used. Here, other vinyl monomers include vinyl esters such as vinyl propionate and vinyl persate; acrylic acid, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate,
Unsaturated organic acids such as methacrylic acid, methyl methacrylate, butyl methacrylate, maleic anhydride, dimethyl maleate, di (2-ethylhexyl) maleate or derivatives thereof; unsaturated fragrances such as styrene and 2,5-dichlorostyrene Group monomers; unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated mono- or dihalides such as vinyl chloride and vinylidene chloride. Of these vinyl monomers, preferred are methyl acrylate, ethyl acrylate, and butyl acrylate.

The vinyl monomer is the olefin polymer 1 described above.
10 to 50 parts by weight, preferably 15 to 30 parts by weight, is added to 00 parts by weight. The addition can be done all at once or in portions. In subjecting the olefin polymer and the vinyl monomer as described above to the graft reaction conditions, a radical generator is usually used except for the reaction by radiation.

(C) Radical generator As the radical generator used in producing the modified polymer, a general-purpose radical generator can be used, but in view of the preferred graft reaction method described later, the decomposition temperature is It is preferably 50 ° C or higher and oil-soluble. Here, the "decomposition temperature" is a temperature at which the decomposition rate of the radical generating agent becomes 50% when 0.1 mol of the radical generating agent is added to 1 liter of benzene and the mixture is left at a certain temperature for 10 hours. The so-called "decomposition temperature for obtaining a half-life of 10 hours" is meant. If the decomposition temperature is low, the polymerization of the vinyl monomer may progress abnormally, and the polymer of the vinyl monomer may be finely dispersed as a dispersed phase in the olefin polymer. There is a drawback that a homogeneous modified polymer cannot be obtained. However, it is also possible to perform a graft reaction efficiently by performing a stepwise or continuous decomposition by appropriately combining those having a high decomposition temperature and those having a low decomposition temperature.

Examples of such a radical generator include 2,4-dichlorobenzoyl peroxide, t-butylperoxypivalate, o-methylbenzoyl peroxide and bis-3,5,5-trimethylhexanoyl. Peroxide, octanoyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, cyclohexanone peroxide,
2,5-dimethyl-2,5-dibenzoylperoxyhexane, t-butylperoxybenzoate, di-t-
Organic peroxides such as butyl-diperoxyphthalate, methyl ethyl ketone peroxide, dicumyl peroxide, and di-t-butyl peroxide: azo such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) There are compounds, etc.

The amount of the radical generator used is within a range of about 0.01 to 10% by weight with respect to the amount of the vinyl monomer used, and is appropriately adjusted depending on the type of radical generator and reaction conditions. If the amount used is less than this amount, the reaction does not proceed smoothly, while if it exceeds this amount, gel is likely to be formed in the modified polymer and the effect of the present invention is difficult to be exhibited.

2) Preparation of Modified Polymer The modified polymer is produced by subjecting each of these raw material components to a graft polymerization reaction. It is possible to produce a modified polymer by the aqueous suspension graft method described below. It is a particularly preferable method because it is easy to control the amount. That is, an aqueous suspension containing olefin polymer particles, a vinyl monomer and a radical generator is heated to a temperature at which decomposition of the initiator does not substantially occur, and the monomer is mixed with the olefin polymer particles. The amount of unimpregnated free monomer is 2
It is preferable to impregnate the aqueous suspension to a temperature of less than 0% by weight and then further raise the temperature of the aqueous suspension to complete the polymerization of the monomer. This method will be described.

I) Impregnation Step A typical method of impregnating olefin polymer particles with a vinyl monomer in an aqueous medium is to add an aqueous suspension of olefin polymer particles, preferably a radical generator (and, if necessary, And other additives) are added and stirred, or the olefin polymer particles are added to the aqueous dispersion of the vinyl monomer in which the radical generator is dissolved and stirred. Begins. In the impregnation step, industrially, the radical generator should be heated to a temperature at which the radical generator is not substantially decomposed to efficiently perform impregnation, generally at room temperature to
It is preferred to operate at 100 ° C. Since the olefin polymer is relatively compatible with the vinyl monomer, even if less than 20% by weight of the vinyl monomer is liberated before the start of the graft polymerization reaction, it will impregnate the olefin polymer particles during the polymerization. The polymer particles of the vinyl monomer obtained by polymerizing only the free vinyl monomer do not precipitate independently of the modified polymer particles. The impregnation time is usually about 2 to 8 hours.

The amount of the modified polymer particles and the vinyl monomer used in the aqueous suspension with respect to water is usually about 5 to 100 parts by weight per 100 parts by weight of water. Such an aqueous suspension can be maintained in a stable suspended state by simply performing sufficient stirring, but the suspension can be prepared more easily and stably by using an appropriate suspension stabilizer. be able to. As the suspension stabilizer in this case, specifically,
For example, water-soluble polymer substances such as polyvinyl alcohol, methyl cellulose, hydroxy cellulose, anionic surfactants such as alkylbenzene sulfonate, nonionic surfactants such as polyoxyethylene alkyl ether, or magnesium oxide, calcium phosphate, etc. A water-insoluble inorganic salt or the like is used alone or in a mixture of about 0.01 to 10% by weight with respect to water. When the olefin polymer particles are impregnated with the vinyl monomer (and the radical generator, etc.), auxiliary materials such as a plasticizer, a lubricant, and an antioxidant can be simultaneously impregnated (these auxiliary materials are olefin polymers). In some cases, it may already be added to, or it may be added after the graft polymerization reaction).

Ii) Graft Polymerization Step If the temperature of the aqueous suspension thus prepared is raised to a temperature above the temperature at which the radical generator used decomposes at an appropriate rate, the impregnated vinyl monomer unit The body polymerizes to produce modified polymer particles. It is preferable to appropriately stir the aqueous suspension during the polymerization. The polymerization temperature is generally 50-100.
It should be appropriately selected within the range of ° C, but it does not have to be constant throughout the polymerization process. When the polymerization temperature exceeds 100 ° C., not only gelation is likely to occur, but also agitation tends to cause splitting of the particles into fine particles and fusion of the particles into agglomerates.

The polymerization time is usually about 2 to 10 hours. After the polymerization, if a treatment similar to the post treatment of a usual aqueous suspension polymerization of vinyl monomer (for example, styrene) is performed,
Modified polymer particles are obtained in which the shape of the olefin polymer particles used is substantially maintained. Therefore, the olefin polymer used before the reforming may be in the form of powder, but it is more convenient to be in the form of particles in consideration of handling during the subsequent molding process. That is, the particle size is preferably one that is usually used as a molding material, since the modified polymer produced can be directly used as a molding material, and generally, the average particle diameter is 1 to 8 mm, preferably 3 It is about 7 mm. No significant change is observed in the dimensions before and after the modification treatment. The modified polymer obtained contains 1% by weight of vinyl monomer.
More preferably, it is graft-copolymerized in an amount of from 2% by weight to 100% by weight.

(3) Blending and molding of composition The blending ratio of each component constituting the composition of the present invention is as follows: (a) 100 parts by weight of fluorine-containing resin, (b) 5 to 300 parts by weight of silane-modified olefin polymer. And (c) modified polymer 5 to 50
Parts by weight, preferably (a) 100 parts by weight of a fluorine-containing resin, (b) 15 to 200 parts by weight of a silane-modified olefin polymer and (c) 7 to 40 parts by weight of a modified polymer, and more preferably (a) ) 100 parts by weight of fluorine-containing resin, (b) 20 to 150 parts by weight of silane-modified olefin polymer, and (c) 10 to 30 parts by weight of modified polymer. If the amount of the silane-modified olefin polymer is less than the above range, the effect of crosslinking, that is, the effect of improving solvent resistance is not sufficiently exhibited, and if it exceeds the above range, the properties of the fluorine-containing resin are not exhibited, which is not preferable.
On the other hand, if the amount of the modified polymer is less than the above range, the compatibility between the fluorine-containing resin and the silane-modified olefin polymer cannot be sufficiently expressed, and thus a uniform molded article cannot be obtained. If the amount exceeds the above range, the solvent resistance is improved. The effect is not sufficiently expressed, which is not preferable.

The composition of the present invention includes the above (a) and (b).
In addition to the essential components (c) and (c), additional components can be added in an amount within a range that does not impair the effects of the present invention. Examples of additional components include other thermoplastic resins, rubber substances,
Inorganic fillers, pigments, plasticizers, various stabilizers (light stabilizers,
Antiblocking agents, lubricants, antioxidants, antistatic agents, etc.) and the like.

Although the above components may be dry blended and directly molded, they are generally kneaded in advance with an ordinary kneading machine such as a roll, a Banbury mixer or an extruder to give a composition, which is then subjected to molding. The molding can be carried out by means generally used for thermoplastic resins, such as injection molding, hollow molding, compression molding, extrusion molding and the like.

(4) Crosslinked Molded Article A crosslinked molded article can be produced by exposing the crosslinkable fluorine-containing resin composition produced above to exposure in a water atmosphere in the presence of a silanol condensation catalyst for crosslinking. . As the silanol condensation catalyst, the above-mentioned JP-B-48-17 is used.
As disclosed in Japanese Patent Publication No. 11, etc., for example, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate and the like can be mentioned. The catalyst is
It can be blended with the above-mentioned crosslinkable fluorine-containing resin composition before molding, or can be applied or impregnated into the crosslinkable fluorine-containing resin after molding as a solution or dispersion. The amount of the catalyst used is generally 10 times the crosslinkable fluorine-containing resin composition 10.
It is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 0 parts by weight. After molding the crosslinkable fluorine-containing resin composition into a desired shape, the molded body is cooled to room temperature to 200.
The crosslinked molded article can be produced by contacting with water (liquid or vapor) at a temperature of normal temperature to 100 ° C for 10 seconds to 1 week, usually for 1 minute to 1 day.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following examples. [Production of Modified Olefin Polymer] Reference Example 1 20 kg of pure water, 0.6 kg of tribasic calcium phosphate as a suspending agent and 0.6 g of sodium dodecylbenzenesulfonate were mixed into a 50 liter autoclave to prepare an aqueous medium. 7 kg of an ethylene-vinyl acetate copolymer (MFR: 150 g / 10 minutes, vinyl acetate content: 28% by weight) having a particle size of 3 to 4 mm was added to and stirred and suspended.
Separately, 64.5 g of t-butyl peroxypivalate and 3.6 g of benzoyl peroxide were dissolved in 3 kg of vinyl acetate, this was added to the above suspension system, and nitrogen was introduced into the autoclave to bring the inside of the system to 0. Pressurized to 5 kg / cm ² . Further, the temperature inside the autoclave was raised to 50 ° C., and the mixture was allowed to stand for 3 hours while stirring at this temperature to impregnate the ethylene-vinyl acetate copolymer particles with vinyl acetate containing a polymerization initiator. Next, this suspension was heated to 63 ° C., and allowed to stand for 8 hours for polymerization while stirring at this temperature, and further heated to 70 ° C. for 2 hours and heated to 80 ° C. for 1 hour. Then, the polymerization was completed.
After cooling, the solid content was taken out and washed with water to obtain 10 kg of modified ethylene-vinyl acetate copolymer particles.

Reference Example 2 20 kg of pure water, 0.6 kg of tribasic calcium phosphate as a suspending agent and 0.6 g of sodium dodecylbenzene sulfonate were mixed into a 50 liter autoclave to prepare an aqueous medium, and a particle size of 3 to 4 mm was added thereto. 7 kg of ethylene-methyl acrylate copolymer (MFR: 20 g / 10 min, methyl acrylate content: 25% by weight) was added and stirred to suspend. Separately, t-butyl peroxypivalate 64.
5 g and 3.6 g of benzoyl peroxide were dissolved in 3 kg of methyl acrylate and added to the above suspension system,
Nitrogen was introduced into the autoclave to bring the inside of the system to 0.5 kg / cm ^2.
Pressurized to. Furthermore, the temperature inside the autoclave is raised to 50 ° C,
The mixture was left at this temperature for 3 hours with stirring to impregnate the ethylene-methyl acrylate copolymer particles with methyl acrylate containing a polymerization initiator. Next, the suspension was heated to 63 ° C., and allowed to stand for 8 hours to polymerize while stirring at this temperature, and further heated to 70 ° C. for 2 hours and heated to 80 ° C. for 1 hour.
The time was maintained to complete the polymerization. After cooling, the solid content was taken out and washed with water to obtain 10 kg of modified ethylene-methyl acrylate copolymer particles.

Examples 1 to 3 Polyvinylidene fluoride (Kainer 72 manufactured by Penwalt Co.)
0), a silane-modified ethylene-vinyl acetate copolymer (“Linklon” XVF750N manufactured by Mitsubishi Petrochemical Co., Ltd.) and the modified ethylene-vinyl acetate copolymer obtained in Reference Example 1 were mixed in the proportions shown in Table 1. Then, it was melt-kneaded at 200 ° C. with a 30 mm diameter twin-screw extruder to produce a crosslinkable fluorine-containing resin composition.
After mixing 100 parts by weight of the obtained composition with 0.05 part by weight of dibutyltin silarate, a sheet having a thickness of 1 mm was formed by a 20 mm sheet extrusion sheet forming machine (L / D = 28). The obtained sheet was left in a steam bath at 80 ° C. to form a crosslinked molded body. The obtained crosslinked molded article,
And tensile strength (according to JIS K6758), tensile elongation (according to JIS K6758), elastic modulus (JIS K71) of the molded body after being left for 7 days at room temperature in acetone.
06) and the dimensional change rate (JIS K6301). The results are shown in Table-1.

Example 4 Crosslinking molding was performed in the same manner as in Example 1 except that the modified ethylene-vinyl acetate copolymer produced in Reference Example 2 was used in place of the modified ethylene-vinyl acetate copolymer. The body was manufactured and its physical properties were evaluated. The results are shown in Table-1.

Comparative Example 1 A crosslinked molded article was produced in the same manner as in Example 1 except that the modified ethylene-vinyl acetate copolymer was not used, and its physical properties were evaluated. The results are shown in Table-1.

Comparative Example 2 A crosslinked molded article was produced in the same manner as in Example 1 except that the silane-modified ethylene-vinyl acetate copolymer was not used, and its physical properties were evaluated. The results are shown in Table-1.

[0030]

[Table 1]

As is clear from the results of the evaluation of physical properties of Comparative Example 3, a simple substance of polyvinylidene fluoride cannot be applied to a field requiring flexibility because of its high rigidity. As a method for softening polyvinylidene fluoride, as shown in Comparative Example 2, it can be softened by alloying with a modified polymer compatible with polyvinylidene fluoride, but the solvent resistance is low. descend. On the other hand, in order to improve the solvent resistance of polyvinylidene fluoride, Comparative Example 1
As shown in, when a silane-modified olefin polymer is blended, it is not compatible with polyvinylidene fluoride,
Elongation decreases. Therefore, it is necessary to use the composition of the present invention containing the components (a), (b) and (c) in order to obtain a crosslinked molded article having good flexibility and solvent resistance. It is easily understood from the results of 1-4.

[0032]

EFFECTS OF THE INVENTION The molded article produced from the fluorine-containing resin composition of the present invention has excellent chemical resistance and flexibility, and thus has a wide range of applications, but particularly for fuel (gasoline) tubes and the like. It is a suitable material for solvent resistant tubes.

Claims (2)

[Claims] 1. (a) 100 parts by weight of fluorine-containing resin (b) Silane-modified olefin polymer 5
300 parts by weight, and (c) 5 to 50 parts by weight of a modified polymer obtained by subjecting an olefin polymer and a vinyl acetate monomer or an alkyl alkylate monomer to a graft reaction condition. Crosslinkable resin composition. 2. A crosslinked molded article obtained by exposing the crosslinkable resin composition according to claim 1 to a water atmosphere in the presence of a silanol condensation catalyst to crosslink.