JPS5930812A - Preparation of high polymeric composite material - Google Patents

Abstract

PURPOSE:To obtain a material usable for single-sided adhesive tapes, etc., by irradiating a high polymeric material with radiation, heating one side of the base material, cooling the other side at the same time, bringing a vinyl monomer into contact with the resultant high polymeric material to graft polymerize the vinyl monomer in a content different in the thickness direction. CONSTITUTION:A high polymeric material, e.g. a film, sheet or nonwoven fabric made of a synthetic resin or rubber, is irradiated with radiation, e.g. electron rays, of preferably 2-30 megarads dose to generate (hydro)peroxides or polymeric radicals. One side of the above-mentioned high polymeric material is then heated preferably at 50-100 deg.C, and the other side is cooled to preferably -50- +20 deg.C to give a concentration gradient to active sites of the peroxides, etc. present in the base material. The base material is then brought into contact with a vinyl monomer to graft polymerize the vinyl monomer in an amount different in the thickness direction of the base material and give the aimed composite material having functional properties different in the thickness direction of the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polymer composite material.
The present invention relates to a method for producing a composite polymer material in which different types of vinyl polymers are graft-polymerized at different contents in the thickness direction, thus having different functionalities in the thickness direction.

Conventionally, methods for imparting new functionality to polymeric materials include adhering different types of polymeric materials to their surfaces, or coating and drying solutions of different types of polymeric materials on their surfaces. A widely known method is to form a layer of a different type of polymer material on the surface of an initial polymer material. However, with this method, the adhesion of the different polymer layer formed on the original polymeric material is generally poor, and when using an adhesive diluted with a solvent, the original polymeric material may be damaged. In addition to the risk of deterioration, there is also the risk of causing problems such as environmental pollution.

For this reason, a method has been proposed in which a polymer material is graft-copolymerized with different types of monomers, and the different types of polymers are chemically bonded to the original material (Japanese Patent Laid-Open No. 49738/1983).

According to this method, the adhesion between the original material and the different polymer is excellent, but in general, the monomer is graft-copolymerized uniformly in the thickness direction of the polymer material. It is not possible to add new functionality to the material so that it has anisotropy in the thickness direction.

The present invention has been made in view of the above, and is a method for producing a composite polymer material in which vinyl polymers are graft-polymerized at different contents in the thickness direction of the polymer, and thus have different functionality in the thickness direction. The purpose is to provide

The method for producing a composite polymer material according to the present invention involves irradiating a polymer material with radiation to generate peroxide, hydroperoxide, or polymer radicals, and then heating one side of the polymer material while heating the other side. After cooling, the method is characterized in that a vinyl monomer is brought into contact with the polymer material to form a vinyl polymer at a content rate that varies in the thickness direction of the polymer material.

In the present invention, radiation includes α rays, β rays, γ rays,
Although X-rays, neutron beams, electron beams, ultraviolet rays, etc. can be used, electron beams are preferably used. Furthermore, although the radiation dose depends on the type and thickness of the polymer material, it is usually 1 to
It is 100 megarads. When it is less than 1 megarad,
This is because the rate of graft copolymerization in the treated polymeric material is low and the amount of grafted heteropolymer is also small.
On the other hand, if it exceeds 100 megarads, there is a risk of decomposition and deterioration of the polymer material. A particularly preferred radiation dose is between 2 and 30 megarads.

The radiation atmosphere may be air, oxygen, or an inert gas, but it is preferable to perform radiation irradiation in the presence of oxygen because the graft copolymerization of vinyl monomers described below proceeds smoothly.

Next, according to the present invention, one side of the polymeric material that has been irradiated with radiation and in which peroxide, hydroperoxide, or polymer radicals have been generated is heated, and the other side is cooled. Even if peroxide, etc. is uniformly generated in the polymer material in the slender direction due to radiation irradiation, this heating and cooling treatment creates a concentration gradient at the active sites where graft copolymerization of peroxide, etc. takes place within the polymer material. As a result, by bringing the monomer into contact with the monomer and heating it, the vinyl polymer is graft-copolymerized into the polymer material at different contents in the thickness direction.

The heating and cooling temperature of polymeric materials depends on the type and thickness of the material used, but in the case of films or sheets, the appropriate heating source temperature is usually 50 to 100°C, and the cooling source temperature is constant. 50~20℃ is suitable, and the temperature difference between the two is 30℃.
It is desirable that the temperature is above ℃.

However, when the polymeric material has heat resistance, the heating temperature can be increased to make the temperature difference larger than above.

The method of heating one side of the polymeric material and cooling the other side is not particularly limited. For example, if the polymeric material is a film or sheet, the cooled side may be brought into contact with a metal plate or metal roll kept at a constant low temperature, and the other side may be heated with an infrared heater, a heating roll, or the like. It goes without saying that when the film or sheet is long, one side can be heated and the other side can be cooled continuously.

The polymeric material used as the base material in the present invention is a film, sheet, woven fabric, nonwoven fabric, etc. made of synthetic resin or rubber. Synthetic resins and rubber are not particularly restricted,
Although various materials can be used, specific examples include polyethylene,
Polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, ethylene-propylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyester, polyamide, polyacrylic acid ester, polymethacrylate ester, A
Synthetic resins such as BS resin, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polycarbonate, polysiloxane, epoxy resin, natural rubber, rubber such as NBR, SBR, polyisobutylene, polybutadiene, isoprene-isobutylene copolymer, etc. I can do it.

Moreover, as the vinyl monomer, there are no particular restrictions as long as it can be radically polymerized, and various types can be used, and are appropriately selected depending on the functionality to be imparted. For example, such vinyl monomers generally include α,β-unsaturated carboxylic acids, esters thereof, substituted vinyl monomers, allyl monomers, and the like. Specific examples of these include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and acrylic acid.
2-ethylhexyl, hydroxyethyl acrylate, methacrylic acid, methyl methacrylate, hydroxyethyl methacrylate, crotonic acid, itaconic acid, maleic acid, diethylaminoethyl methacrylate, sulfopropyl acrylate, glycidyl methacrylate, vinyl acetate,
Examples include vinyl chloride, vinylpyridine, vinylpyrrolidone, vinylcarbazole, acrylonitrile, tetrafluoroethylene, butadiene, isoprene, propylene, styrene, styrene sulfonic acid, ethylene, diallylamine, etc., but acrylic acid with high graft copolymerizability, Methacrylic acid or esters thereof are preferably used.

In the present invention, the base material irradiated in this way is treated with a vinyl monomer (including a solution) from which oxygen has been removed.
to graft-copolymerize the vinyl monomer onto the base material. The method of bringing the vinyl monomer into contact with the substrate is usually by applying the vinyl monomer to the substrate or dipping it into the vinyl monomer. When the base material is brought into contact with the vinyl monomer and graft copolymerized in this manner, heating is usually performed. The heating temperature at that time varies depending on the base material and the type of nanatsuma, but is usually 40 to 150℃.
It is. However, if the base material has heat resistance such as a fluoropolymer, it can also be heated to 300°C or higher.

As described above, according to the present invention, after irradiating a polymeric material as a base material with radiation, one side of the base material is heated and the other side is cooled to remove grafts such as peroxide contained in the base material. A concentration gradient is applied to the active sites for copolymerization, and then the vinyl monomer is brought into contact with the base material to graft copolymerize the vinyl monomer, so that the vinyl monomer is graft copolymerized in different amounts in the thickness direction of the base material. polymerization, thus obtaining a composite material with varying functionality across the thickness of the substrate. Therefore, the composite polymer material according to the present invention can be applied to, for example, anisotropic selectively permeable membranes, battery separators, single-sided adhesive tapes, etc., and can be applied by selecting the vinyl monomer to be graft copolymerized. , surface activity, weather resistance, and other desirable properties or functionality depending on the purpose and use can be added.

Examples of the present invention are listed below, but the present invention is not limited to these Examples in any way.

In addition, in the following, the grafting rate is defined by the formula % formula % (), where W. is the weight of the base polymer before graft copolymerization, and W6 is the weight of the graft copolymer.

Example 1 A low density polyethylene film having a thickness of 100 μm was irradiated with an electron beam of 20 megarads in air using an electron beam accelerator with an acceleration voltage of 2 million V and a beam current of 5 mA.

Next, the back side of this film was cooled by contacting it with an iron plate kept at 20°C, and the front side was heated by contacting it with a hot plate having various temperatures shown in Table 1 for 1 minute, and then each film was placed in a microtome. The front and back surfaces were scraped by 20 μm each, and the amount of peroxide contained in this was described in "Experimental Chemistry Course 17, Reactions of Organic Compounds (Part 1)" (Nippon Kagaku Complete Edition, published by Maruzen), pp. 620-621. quantified according to the peroxide analysis method of As the results are shown in Table 1,
It was confirmed that the amount of peroxide on the heated front side of the film was smaller than that on the cooled back side, and that the amount of theroxide in the film had a concentration gradient.

Next, nitrogen was blown into the acrylic acid-methanol solution (weight ratio 1:1) to remove dissolved oxygen, and the solution was heated to 70°C.
Each film treated in the same manner as above was immersed in this solution for 15 minutes. After that, each film was immersed in boiling water for 1 hour to extract and remove unreacted monomers and homopolymers, and then heated to 80°C.
It was dried for 2 hours.

Each film graft copolymerized in this way was scraped off to 20 μm on the front and back sides using a microtome, and the graft copolymerization rate was determined from the absorption of carbonyl groups on each side using multiple total internal reflection infrared analysis. However, the results shown in Table 2 were obtained. That is, it was confirmed that the monomers were graft copolymerized at different contents in the thickness direction of the film. In the table, the heating source temperature on the front side corresponds to the experiment number in Table 1.

Example 2 A low density polyethylene film having a thickness of 200 μm was irradiated with an electron beam of 40 megarads in air using an electron beam accelerator with an acceleration voltage of 2 million square meters and a beam current of 5 mA. Next, the back side of this film was brought into contact with a cooling roll kept at 15°C, and the front side was heated for 10 minutes with an infrared heater at 100°C.

Next, butyl acrylate-methanol solution (weight ratio 1:
1) was blown with nitrogen to remove dissolved oxygen, heated to 88°C, and immersed the film in this for 12 minutes. The film was then immersed in hot methanol at 60°C for 1 hour to remove unreacted monomers. The homopolymer was extracted and incubated at 70°C for 30
After drying for a minute, a weight increase of 10 g/rrr was observed.

This film was cut to a width of 25 m, the front side or the back side was attached to a 5US430 bright annealed stainless steel plate, and the film was pressed with a 2 kg rubber roller. After leaving it for 20 minutes, peel it off at a speed of 30 in an atmosphere at a temperature of 25°C.
When the peeling force was measured at 180 degrees at 0 mm/min,
The back side is 260g/25H width, the front side is 15g/
2 S in width, the adhesive strength on the cooling side is significantly larger than the adhesive strength on the heating side, and it can be used as a single-sided adhesive tape.

Claims (1)

[Claims] (1) Peroxide is produced by irradiating a polymer material with radiation.
Hydroveroxy F or polymer radicals are generated, and then one side of this polymeric material is heated and the other side is cooled, and then a vinyl monomer is brought into contact with the polymeric material to contain different contents in the thickness direction. 1. A method for producing a polymer composite material, which comprises forming a vinyl polymer at a certain temperature.