JPH01185376A - Coating fluorocarbon resin and fluorocarbon resin solution - Google Patents

Abstract

PURPOSE:To obtain a fluorocarbon resin having expansibility, flexibility, stain resistance, chemical resistance, weather resistance and nonstickiness, by copolymerizing a vinylidene fluoride monomer and a vinyl acetate with a specified elastomeric fluorocarbon copolymer. CONSTITUTION:A fluorocarbon resin formed by copolymerizing at least one monomer containing at least one fluorinated monomer with a monomer having both a double bond and a peroxy bond in the molecule to produce an elastomeric fluorocarbon copolymer (trunk polymer) having a glass transition temperature below room temperature and grafting 40-70pts.wt. vinylidene fluoride monomer (VDF) and vinyl acetate (VAC) onto 100pts.wt. this trunk polymer. The weight ratio of VDF to VAC in grafting is preferably in the range of 80/20-20/80. When the proportion of VAC is below the lower limit, the adhesiveness to an adherend is decreased, and when it is above the upper limit, the weather resistance and stain resistance are lowered undesirably.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a novel fluororesin for coating that has elasticity, stain resistance, chemical resistance, weather resistance, and non-stick properties. The present invention also relates to a coating fluororesin liquid prepared by dissolving the same in a polar solvent.

(Prior art) Conventional, well-known general polyurethane synthetic leather has a texture and appearance very similar to natural leather, so it is mainly used for bags, bags, footwear, clothing, etc., which are relatively fashionable. Although it is often used as a short-term fashion material, it has a long service life for furniture and guide materials, and due to its hydrolytic nature, which causes it to become brittle in a few years, it has a surface that is stain resistant, chemical resistant, Various proposals have been made for improving weather resistance.

In addition, flexible sheet materials with high tensile strength, such as plasticized PVC membranes reinforced with polyester fibers, are used for tent membranes, store bottom membranes, truck top membranes, etc., but due to long-term exposure, PVC has the drawback that its tackiness increases due to the bleed phenomenon of plasticizers contained in PVC, and that it is contaminated by pollutants such as dust and oil in the atmosphere.

For this reason, fluororesin coating has been proposed as one of these improvement measures.

That is, as a fluororesin film-coated laminate, a method in which a polyvinyl fluoride film is composited with a high-strength fabric via a polyurethane layer (Japanese Patent Application Laid-Open No. 162647/1983) is used.
), heat fusion of polyvinylidene fluoride (Unexamined Japanese Patent Publication No. 1983-
69989) or a sheet (
JP-A-61-61849), PVDP, P
Totono laminations of TFE and PFA have been proposed.

(Problems to be Solved by the Invention) However, although these fluororesins have excellent stain resistance, chemical resistance, and weather resistance, they are not suitable for use as surface coating materials or impregnation materials for base materials. Poor flexibility.

For example, when a PVF film is used as a covering material for a tent material, wrinkles from folding before tent construction may remain on the PVF surface, so it cannot be said to be a surface material that follows the bendability of the sheet material. . One of the problems to be solved by the present invention is to provide a fluororesin surface material having excellent flexibility and flexibility.

Conventionally, the resin surface layer has been formed by laminating a fluororesin film with an adhesive, or by directly coating a fluororesin liquid on a resin base material and drying it to form a film.

Therefore, there are methods that omit the film manufacturing process, but for this purpose, a fluororesin solution is required, and it is also possible that the formed fluororesin film adheres to the base resin or the primer-treated surface interface. is necessary.

(Means for Solving the Problems) The present invention has been made to improve the above-mentioned drawbacks. Copolymerizing one or more monomers containing one or more fluorine-containing monomers and a monomer having both a double bond and a peroxy bond in the molecule,
A fluorine-containing elastic copolymer (stem polymer) whose glass transition temperature is below room temperature is produced, and 40 to 70 parts by weight of vinylidene fluoride monomer and vinyl acetate monomer are added to 100 parts by weight of this backbone polymer. A base material is coated or impregnated with a copolymerized fluororesin and a fluororesin solution for cornering in which the resin is dissolved in a polar solvent.

In the present invention, the substrate to be coated with the soft fluororesin is not limited, but is particularly flexible polymeric material, for example, resin material, P
NBRSCR for VC, PR, urethane, soft fluororesin, and rubber materials.

SBR and the like are suitable target resins, as well as synthetic fibers, glass fibers, knitted and woven fabrics, non-woven fabrics, metals, and the like.

Next, the soft fluororesin, which is the most important feature of the present invention, will be explained.

The present inventors have previously proposed a method for producing a flexible fluororesin in Japanese Patent Publication No. 62-34324. In view of this, new studies and improvements are required, and the soft fluororesin used must contain at least one kind of monomer containing at least one kind of fluorine-containing monomer, and a monomer having both a double bond and a peroxy bond in the molecule. is copolymerized to produce a fluorine-containing elastic copolymer (stem polymer) containing a beroxy group in its molecule and whose glass transition point temperature is below room temperature, and an aqueous emulsion or , backbone polymer 100 in dispersion solvent
It is a fluororesin resin obtained by graft copolymerizing 40 to 70 parts by weight of vinylidene fluoride monomer and vinyl acetate monomer, and it is also a fluororesin liquid dissolved in a polar organic solvent. The backbone polymer in the fluororesin is composed of a fluorine-containing copolymer whose glass transition point temperature is below room temperature, so it exhibits the properties of an elastic body at room temperature and temperatures higher than that of conventional PTFB and PF.
A, PEP XETFE, PCTFE, PVDF
It is extremely flexible compared to fluorophore resins such as PVF, and in addition, it is made to be solubilized in organic solvents by copolymerizing vinylidene fluoride and vinyl acetate.

The present invention is characterized by the use of such a soft fluororesin, but in order to form a thin film layer of the resin on a cloth, sheet, or film substrate such as fiber, glass, or resin, the resin solution solution must be A coating layer can be formed by coating or dipping the material and evaporating the solvent in a dryer.

Existing fluororesins have good resistance to organic solvents, so their solubility is low, and the solubility in organic solvents decreases dramatically as the fluorine content in the polymer increases. However, with the exception of polyvinyl fluoride resin (PVF), film molding has not been implemented. However, PVF is a hard resin, and there is room for improvement as a coating material for resin base materials that require flexibility.

The present invention was made in view of these demands, and its aim is particularly to modify the resin into a solvent-soluble resin.

In addition, in order to be used as a coating resin, adhesion to adherends is required, and another aim is to improve the adhesion to some extent, which is a weak point of fluororesins.

In general, fluororesins are characterized by good non-adhesiveness and stain resistance, but these properties may be impaired by solvent-soluble types and resin modification to improve adhesiveness. However, the present invention utilizes these characteristics without losing them.

The organic solvents used in the resin solution include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA''), N-methylpyrrolidone, 1.3
- Polar organic solvents such as lamellar-2-imidazolidinone, among others <DMP is a general-purpose solvent, and the resin concentration of the solution is at least 150 g / /,
Preferably 200g/7! It is desirable that the coating film is formed on a coating line onto a resin substrate, and under 150 g/Il EJ, the amount of solvent evaporated in the film drying process increases, which is not economical.

As described above, in the present invention, as a method of increasing the solubility in solvents, vinylidene fluoride (VDF) monomer and vinyl acetate monomer (VAC) are added to the fluorine-containing elastic copolymer (steering polymer). The solubility has been greatly improved by graft copolymerizing with other tetrafluoroethylene monomers, chlorotrifluoroethylene monomers, tetrafluoroethylene/ethylene and chlorotrifluoroethylene/ethylene. For polymers, resin swelling is observed in solvents, but 15
Solubilization of any resin with a concentration of 0 g/1 or more is difficult.

In addition, it is appropriate that the total amount of both monomers is 40 to 70 parts by weight based on 100 parts by weight of the host polymer, and the lower limit weight of the If the amount of grafting is less than 1 part by weight, it will become gel-like and difficult to dissolve, and if it exceeds the upper limit part by weight, the flexibility of the resin physical properties will decrease and the rubbery properties that are characteristic of soft fluororesin will be lost, so it will have various flexibility. It becomes undesirable as a covering material for equipment.

In addition, the weight ratio of V-Ko and VAC graft preparation is 80.
/20 to 20/80 is suitable. If the VAC ratio is below the lower limit, the adhesion to the adherend will decrease, and if it is above the upper limit, the weather resistance and stain resistance will decrease, which is not preferable.

In this way, a flexible fluororesin that is soluble in DMF is produced by obtaining a fluorine-containing elastic copolymer (stem polymer) having peroxy bonds in the first stage copolymerization reaction, and in the first stage reaction in the second stage reaction. It is obtained by dispersing peroxy bonds in a dispersion solvent for the obtained copolymer and graft-copolymerizing a V weight and a VAC monomer at a temperature below which radicals are generated.

The polymerization conditions of the resin (temperature, stirring number, autoclave capacity, amount of catalyst, etc.) affect the polymerization degree, and the polymerization degree affects the resin solubility, but since the polymerization reaction is a two-step reaction and is complicated, D of the final material, the graft copolymer
The range of use of the resin may be selected based on its solubility in organic solvents containing MF as a main ingredient.

Examples of unsaturated peroxides used here include unsaturated peroxy esters such as t-butylberoxymethacrylate and t-butylberoxycrotonate, and t-butylberoxyallyl carbonate and P-menthameroxyallyl carbonate. Examples include unsaturated peroxycarbonates.

In addition, the composition of one or more fluorine-containing monomers includes an elastic polymer having a composition of fluororubber, a binary system of vinylidene fluoride (VDF) and hexafluoropylobene (HFP), and a combination of VDF and HFP. Tetrafluoroethylene CT
Examples include a ternary system of VDF and chlorotrifluoroethylene (CTFE), and a binary system of VDF and chlorotrifluoroethylene (CTFE).

Next, to explain the coating film in the present invention in detail, regarding the adhesion of the film, in order to further strengthen the adhesion of the interface between the coating film formed by coating the fluororesin solution and the resin base material, If necessary, a method may be adopted in which a resin solution having good adhesion to the fluororesin is coated on the resin base material in advance and dried to form a primer resin layer. In addition, resins that can be used as brimer resins can be selected through various tests such as the resin and resin base material, adhesion to other materials, solubility in solvents, and durability under the usage environmental conditions. Although the invention does not specify the type of resin, urethane resin, epoxy resin, vinyl acetate resin, nitrile rubber (NBR), etc. are useful as the brimer resin. Further, as a means for dipping, a conventional method of dipping the substrate in a fluororesin solution for coating may be used.

The drying temperature for forming the fluororesin liquid coating film is 50°C to 150°C, preferably 70°C to 120°C.
is within the range of Here, a temperature of 50° C. or lower is not preferable because it not only takes a long time to dry, but also causes a whitening phenomenon in the formed film. Also, 150℃
At a temperature higher than that, the surface smoothness becomes poor due to the bumping phenomenon of the resin solution, which is not preferable.

Examples and comparative examples of the present invention will be specifically described below.

Examples 1 to 4 and Comparative Examples 1 to 7 1. Production of backbone polymer 15 kg of water was placed in a 301 capacity stainless steel autoclave.
, 30 g of potassium persulfate, 40 g of ammonium perfluorooctanoate and 30 g of t-butylberoxyallyl carbonate were added, and after evacuation, vinylidene fluoride monomer 3
．． 8kg, chlorotrifluoroethylene monomer 2.3k
A polymerization reaction was carried out at a temperature of 51° C. for 19 hours with stirring, and at the end of the reaction, the rotation speed of the stirring was increased to precipitate the polymer to obtain a powdery polymer. The yield after washing with water and drying was 5.0 kg, and the amount of active oxygen based on t-butylberoxyallyl carbonate in the copolymer was determined to be 0.041% by iodometric titration.

2. Production of graft copolymer 144 g of the backbone polymer obtained by the above copolymerization reaction and 113,500 g of Freon R were placed in a stainless steel autoclave, and after exhausting, the monomers shown in Table 1, V-Ko and V-
AC was charged and graft polymerization was carried out at 98°C for 22 hours.

The produced polymer was separated from the catalyst, washed with water, and dried to obtain the results shown in Table 1.

The composition ratio of V-leaf and VAC contained in the graft portion of the obtained resin was determined by quantitative analysis of fluorine using the alizarin complex method.

3. Solubility test (part 1) 50 g of the polymer obtained by the above graft copolymerization was
00ml beaker, add 250ml of N,N-dimethylformamide (DMF'), stir for 20 minutes using a laboratory disperser made by Mitamura Riken Kogyo, and after leaving it at room temperature day and night, return to the laboratory. After stirring for 5 minutes with a disperser, the polymer solution was allowed to stand, and the properties of the polymer solution were observed. Those that could be dissolved were marked with ○, and those that were difficult to dissolve were marked with ×.

4. Solubility test and measurement of shear modulus (part 2) The viscosity of the polymer obtained by the above graft copolymerization at 25° C. was measured using a B-type precision needle.

In addition, after masticating these graft copolymers with a heated roll, a 1 mm thick sheet was formed using a heated press, and a torsional free damping type viscoelasticity measuring device (RD-1100AD manufactured by Resca) was used.
Mold, test piece dimensions, 8cm x Icm x 1mm thickness)
The shear modulus was measured at 30°C. The results are shown in Table 1.

5. Adhesiveness test of coating film Using the graft copolymer described above, various coating resin base materials were used, such as two-component polyurethane (manufactured by Dainippon Ink ■, Crisbon C4365) or soft PVC (manufactured by Central Glass ■,
Resin C31300, plasticizer Ro0P60 parts mixed) and N
After treating the surface of the base material with primer resin (film thickness, approx. 3 μm) using BR (Iruma rubber sheet), a coating film is formed using a solution, and its adhesion is tested for cantilever fatigue of plastic. After applying 100,000 vibrations according to the test (ASTM D 671), the adhesion of the film after the test was evaluated, and those showing good adhesion were rated ○, and those showing slightly poor adhesion were rated △.
In Table 1, inferior results are marked with an x.

6. Sunshine weather test specimen sheet (1 mm thick) was placed in a sunshine weather tester (manufactured by Suga Test Instruments, carbon arc 63℃, water sprinkling 1
2 minutes/hour) for 1,000 hours, and the strength retention and elongation retention were measured in a tensile test (ASTM D638), and the results are shown in Table 1.

7. Contamination resistance and chemical resistance test For the various resin specimens shown in Table 1 and the specimens whose surfaces were coated with the fluororesin, engine oil and 10% H were placed on the specimens held horizontally.
(J! Drop the aqueous solution test solution about 1 to 1.5 m!!
After 4 hours, the sample was wiped dry with a compress, and the test solution was again dropped on the same spot 7 times, and evaluated by visual observation.

The results are shown in Table 1.

-17= From the results in Table 1, if the amount of VDF and VAC monomers grafted to 100 parts by weight of the backbone polymer is less than 40 parts by weight (Comparative Example 6.7), it is difficult to dissolve the polymer and the polymer becomes gel-like. Moreover, if it exceeds 70 parts by weight (Comparative Example 2.4
), the shear modulus of the polymer increases and the film becomes hard, making it undesirable to use as a surface material for flexible resins. Therefore, if the graft polymerization is carried out within the above range, the resin coating solution will have high solubility and flexibility.
Forms a surface coating that is adhesive and stain resistant.

(Effects of the Invention) The fluororesin for coating produced according to the present invention is modified as a solvent-soluble resin, and in addition, it has improved adhesion to substrates and is suitable as a coating material for soft substrates. can get.

Patent applicant: Central Glass Co., Ltd.

Claims (2)

[Claims] (1) One or more monomers containing at least one fluorine-containing monomer and a monomer having both a double bond and a peroxy bond in the molecule are copolymerized, and the glass transition temperature thereof is at room temperature. The following fluorine-containing elastic copolymer (stem polymer) is produced, and 40 to 70 parts by weight of vinylidene fluoride monomer and vinyl acetate monomer are graft copolymerized to 100 parts by weight of this backbone polymer. Fluororesin for coating. (2) The fluororesin liquid for coating according to claim 1, wherein a polar solvent is added to and dissolved in the fluororesin for coating.