JPS59204624A - Covering material having improved adhesion - Google Patents

Abstract

PURPOSE:A covering material, obtained by incorporating a specific polyacrylate of polypentaerythritol with a specific polyfunctional acrylate in a specific proportion, and incorporating a specific amount of a photosensitizer therewith, and capable of exhibiting improved adhesion to molded polypropylene articles and films. CONSTITUTION:A covering material obtained by incorporating (A) a polyacrylate of polypentaerythritol expressed by formula I (three or more of X11, X12, X13, Xn2, Xn3 and X14 are groups expressed by formula II; the rest are OH groups; n is an integer 1-5), preferably dipentaerythritol triacrylate is incorporated with (B) a polyfunctional acrylate having two or more urethane bonds at (70:30)- (97:3), preferably (80:20)-(95:5) weight ratio between the components (A) and (B), and 0.1-10pts.wt., preferably 1-6pts.wt. photosensitizer, e.g. benzoin butyl ether, is incorporated with 100pts.wt. above-mentioned mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating material that forms a crosslinked cured coating film by irradiation with ultraviolet rays in an air atmosphere, and particularly to a coating material that has excellent adhesion to polypropylene molded products, films, and the like.

Polypropylene resin has many properties such as excellent mechanical, optical and chemical properties, good moldability, low price, and low specific gravity, and is therefore used in an extremely wide range of applications.

However, since polypropylene resin is non-polar, paints made from conventional alkyd resins, acrylic resins, epoxy resins, urethane resins, etc. have almost no adhesion. Therefore, as a method for coating polypropylene materials, acid-modified polypropylene, such as atactic polypropylene modified with maleic anhydride, ethylene-proylene copolymer modified with maleic acid, or a mixture of chlorinated polypropylene and acrylic resin, can be used as a primer. Alternatively, a method using a copolymer or the like has been proposed.

However, such methods have poor interlayer adhesion with the top coat, solvent resistance, and long-term durable adhesion.Furthermore, these primers are dissolved in large amounts of organic solvents, and from the viewpoint of resource and energy conservation, the spatulas are also organic. It has been desired to develop a coating material that uses less solvent, has excellent durable adhesion, and has excellent coating performance such as solvent resistance and hardness in one coat.

As a result of intensive studies to achieve the above object, the present inventors discovered the identified polyacrylate (5) of polypentaerythritol and the identified polyfunctional acrylate (5).
The present invention was achieved by discovering that a coating material containing a photosensitizer in a mixture with B) is effective.
) (wherein X11, X+2, X18, Xn2, Xns, X+
At least 6 of 4 are CHx=C-Coo- groups, the rest are 10H groups, and n is an integer from 1 to 5. ) Polyacrylate of polypentaerythritol having six or more acryloyloxy groups in one molecule (8)
and polyfunctional acrylate (B) having at least two urethane bonds in the molecule in a weight ratio of (A): (B)
= mixture 100 in the range of 70:30 to 97:3
This coating material has excellent adhesion and contains 0.1 to 10 parts by weight of a photosensitizer.

The coating material of the present invention can be used in one coat on polypropylene molded products or films, and has superior coating performance such as adhesion, solvent resistance, hardness, and durability, and does not require the use of organic solvents. This is a small amount of interest.

In the present invention, the purpose can be fully achieved by using polyacrylate of polybenquerythritol represented by the general formula (5), but in particular, from the viewpoint of curability, hardness, adhesion, etc. Preferably, pentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, etc. are used.

Therefore, if the number of CH2=C-Coo- groups in the compound represented by the general formula (5) is less than 6, the above object of the present invention cannot be achieved.

In the present invention, polyfunctional acrylate (B) having at least two urethane bonds in the molecule refers to a polyisocyanate compound and an acrylic monomer containing a hydroxyl group, or an oligomer containing an acryloyl group and a hydroxyl group, and It is obtained by reacting with a polyhydric alcohol if necessary.

Examples of the polyisocyanate compound include aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexane diisocyanate, isophorone diisocyanate, and methylcyclohexane-2,-4-(or 2,6-).
Examples include diisocyanates, alicyclic diisocyanates such as 4,4'-methylenebiscyclohexyl isocyanate, and aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate. Preference is given to using diisocyanates or cycloaliphatic diisocyanates. Furthermore, examples of hydroxyl group-containing acrylic monomers and oligomers containing acryloyl and hydroxyl groups include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyhexyl acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate, and the like. .

Examples of polyhydric alcohols include ethylene glycol, propylene glycol, phthanediol, hexanediol, diethylene glycol, dipropylene glyco,
-ol, openentyl glycol, 1,4-citalohexane bis-methanol, trimethylolpropane, trimethylolethane, hexanetriol, glycerin,
Examples include pentaerythritol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polycaprolact/and polyester polyol.

In the present invention, the production of polyfunctional decrylate (B) is as follows:
It may be carried out by a conventional method, for example, a known method for producing a polyfunctional acrylate by a solution polymerization method, a Lema solventless method, or the like. The blending ratio of the polyfunctional acrylate (13) and polyacrylate (5) obtained in this way is as follows in terms of weight ratio: The ratio is ~95:5.If the polyacrylate (5) is less than 70% by weight or if the polyacrylate (A) is 97% by weight, the adhesion to lume etc. is poor and it cannot be used as a coating material for polypropylene.

In the present invention, the above-mentioned mixture, that is, photocurable resin 10
0.1 to 10 parts by weight of the photosensitizer is blended with respect to 0 parts by weight. From the viewpoint of curability, it is preferable to add 1 to 6 parts by weight.

Examples of photosensitizers used in the present invention include benzoin-based sensitizers such as hapensoin butyl ether and benzine methyl ether, 2,4-jethoxyacetophenone, P-chlorobenzophenone, and benzophenone. Ketone sensitizer, asohisisobutyronitrile, 2,2
Examples include azo sensitizers such as '-azobis-(2<4>-dimethylvaleronitrile)azobenzene, and quinone sensitizers such as anthraquinone and phenanthraquinone.

The coating material obtained may be added with various additives as necessary, such as leveling agents, antifoaming agents, surfactants, colorants, pigments, fillers, etc., as long as the characteristics of the present invention are not impaired. Agents, matting agents, organic solvents, etc. can be added for the purpose of improving film characteristics.

Various types of polypropylene resins are used to manufacture polypropylene molded products and films, which are the main targets for the use of the coating material of the present invention, depending on the purpose, but stereoregular polypropylene, propylene, and other In combination with olefins, polymers, and mixtures thereof with other resins or appropriate amounts of fillers such as talc and calcium carbonate, coloring agents, etc. can be mentioned.

Next, as a method for forming a film of the coating material of the present invention on a base material,
Any method can be used, but typical examples include a method of coating by dipping the substrate, a method using a spray gun, a method using a roll coke, a flow coater, and a Clavia coater.

The ultraviolet rays necessary for curing the coating material of the present invention are photochemically active electromagnetic waves having a wavelength generally in the range of 200 to 500 nm. As such an ultraviolet light source, commonly used ones such as a carbon arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, an ultraviolet fluorescent lamp, etc. can be used. The time required for irradiation depends on the type and content of the photosensitizer used in the coating material used, the type and output of the light source used for irradiation, the distance from the light source to the object to be coated, and other conditions. Depending on the situation, it is possible to achieve the desired goal with irradiation for several seconds depending on the adjustment of these conditions.

The coating material of the present invention can be used as a transparent protective coat, a colored protective coat, etc. for polypropylene molded products and films, and is therefore useful.

Next, the present invention will be further explained with reference to Examples and Comparative Examples. In addition, unless otherwise specified, parts and proportions are based on weight.

Synthesis Example 1 382 parts of ethyl acetate, 67 parts of trimethylolpropane, and 6 parts of isophorone diisocyanate were charged into a flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas blowing device, and the temperature was raised while blowing nitrogen gas into the reactor. The internal temperature was maintained at 75-85°C and the reaction was carried out for 6 hours. Next, after cooling, 1-174 parts of hydroxyethyl acrylate was charged while blowing air instead of nitrogen gas.
The temperature was further raised to 75 to 85°C, and the reaction was carried out for 4 hours. After the reaction, 5 parts of isopropyl alcohol was added to eliminate residual NCO. Thus, polyfunctional acrylate with a non-volatile content of 60%
1-B-1 Ibby 4I Buko.

Synthesis Example 2 In a flask similar to Synthesis Example 1, 378 parts of triol was added, a ring-opening polymer of Plaxel 603 (trade name, ε-caprolac), average molecular weight 61D), manufactured by Daicel Chemical Industries, Ltd. 155
1 to 252 parts of hexamethylene diisocyanate were charged, and the reaction was carried out in the same manner as in Synthesis Example 1. Next, 174 parts of hydroxyethyl acrylate was charged and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain polyfunctional acrylate B with a non-volatile content of 60%.
-2 was obtained.

Synthesis Example 6 Add Orestar NP-1000 to the same flask as Synthesis Example 1.
(Product name manufactured by Mitsui Toatsu Chemical Co., Ltd., water adduct of Hegisamethylene diisocyanate, 75% non-volatile content, effective NCO
%-17%) ioo part and 56 parts of hydroxypropyl acrylate were charged, and the reaction was carried out in the same manner as the latter reaction of Synthesis Example 1 to obtain polyfunctional acrylate B-6 with a non-volatile content of 867%.
I got it.

Example 1 Polyfunctional acrylate B-1 Roro, 3 obtained in Synthesis Example 1
part and dipentaerythritol pentaacrylate) 80
1 part, benzoin isobutyl ether and 4 parts of benzoin isobutyl ether. The blending ratio of (5):(B) in this coating material was 80:20. The viscosity of this sacrificial material was adjusted to 3 parts per second using Ford Cup/164 toluene, and Noblen B J Hl-1-M (trade name, stereoregular polypropylene resin manufactured by Mitsui Toatsu Chemical Co., Ltd.) was prepared. A polypropylene molded product was coated to a coating thickness of 10 to 15 microns, and cured by irradiating it with ultraviolet rays for about 4 seconds from a height of 15 on using a commercially available high-pressure mercury lamp (80 W/cm'). The properties of this coating are shown in Table 2.

Example 2. '5 and Comparative Examples 1 to 4 Example 1 was prepared using the same method as Example 1 and the formulation shown in Table 1.
It was cured by irradiation with ultraviolet rays in the same manner as above. The properties of this coating are shown in Table 2.

Tests and Test Methods (a) Adhesion; Curved Cellophane Tape Peeling Test Cut 100 gobbles with 1% IJ, perform 11 peeling tests with cellophane tape, and indicate the number of remaining gobbles.

(1)) Solvent resistance; JIS thinner was soaked in gauze and the condition was visually judged after rubbing 100 times.

(c) Stain resistance; After staining with red and black marker ink for 24 hours, the condition was visually judged after wiping with methanol.

(d) Scratch resistance: The condition after being rubbed with Steel Wool 1110000 was visually judged.

(e) Person L: Visually judge the condition after 1000 hours of irradiation with the Zanshine Weather-Ometer.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1) General formula (wherein X+1, X+2, X18, Xn2, X11s,
At least 6 out of +4. n2=c-6oo- group, the rest are 10H groups, and 11 is an integer from 1 to 5. ) Polyacrylate (5) of polypentaerythritol shown in ) and polyfunctional acrylate (B) having at least two urethane bonds in the molecule in a weight ratio (A):
(B)=Mixture 1 consisting of a range of 70:30 to 97:3
A coating material with excellent adhesion, consisting of 0.00 parts by weight and 0.1 to 10 parts by weight of a photosensitizer. 2) At least one compound in which the monomer represented by general formula (3) is selected from dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentae, lythritol pentaacrylate, and dipentaerythritol hexaacrylate. The covering material according to claim 1.