JPH0121162B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition that is cured by ultraviolet light. More specifically, various base materials, especially polyethylene terephthalate (hereinafter abbreviated as PET)
The object of the present invention is to provide a resin composition that is cured by ultraviolet rays and has excellent adhesion to base materials such as films and molded products made of resins. Conventional plastic films, plastic moldings, etc. differ in chemical structure, molecular weight, molecular weight distribution, shape of the main chain of the molecular structure, presence or absence of polarity, stereoregularity, etc. depending on the materials used. In order to improve the adhesion to the base material, pre-treatment methods such as surface treatment with solvents, coupling agents, surfactants, etc., wet treatment methods such as chromic acid mixed solution treatment, phosphoric acid solution treatment, and satinizing method are used. Alternatively, dry processing methods such as corona discharge treatment, ultraviolet irradiation treatment, gas flame treatment, and plasma treatment have been used, and the same applies to films and molded products made of PET resin. However, when using the above-mentioned wet processing method, there is a problem in terms of pollution caused by the discharge of the processing liquid, and dry processing requires physical means to partially change the polarity, shape, etc. of the plastic surface, making the process complicated. Due to the difficulty of sufficiently processing molded products that have been processed to a high degree of shape, and from the standpoint of energy and resource conservation, there is a strong desire to shorten the process. Things were desired. As a method to solve these problems, i.e. to improve the adhesion with plastic films or molded objects without physical or chemical treatment, a composition that can be cured by ultraviolet rays is applied, and a film is formed by irradiating the composition with ultraviolet rays. It has been proposed (Japanese Unexamined Patent Publication No. 49-128067). However, although this method is effective to some extent for polyolefin resin, it is not effective for films and molded products made of untreated PET resin.
No effect on improving adhesion was observed. The inventor of the present invention has completed the ultraviolet curable resin composition of the present invention as a result of intensive studies on methods for improving the adhesion to untreated PET resin. As a resin composition that satisfies the above object, an ultraviolet curable resin composition comprising a compound (A) having at least one ethylenically unsaturated group in the molecule and a photopolymerizable sensitizer has the general formula (B). (In the formula, R ₁ is a hydrogen atom or a methyl group, R ₂ and R ₃ are each a hydrogen atom or an alkyl group, which are the same or different,
acrylic monomer (n is an integer of 1 to 3)
0.5% by weight or more of (B) and 10% by weight or less, and 90% by weight of an ethylenically unsaturated monomer copolymerizable with (B)
Copolymer (C) with a number average molecular weight of 1,000 to 10,000 obtained by copolymerizing 99.5% or more by weight or less is mixed so that 70/30<(A)/(C)≦95/5 (weight ratio). The present invention provides an ultraviolet curable resin composition having improved adhesion to polyethylene terephthalate film. In the present invention, the PET resin which is a typical base material is usually a polyester resin obtained by polycondensation of terephthalic acid or lower alkyl terephthalic acid ester and ethylene glycol.
Resins having an intrinsic viscosity in the range of 0.3 to 0.9 are typical, but resins in which other components such as isophthalic acid are copolymerized as raw materials in addition to the above-mentioned main raw materials are also included. In the present invention, the compound (A) having at least one ethylenically unsaturated group in the molecule may have an ethylenically unsaturated group that can be polymerized. and (b) polyester-based polyesters, which are esters of hydroxyl group-terminated esters of various polymerization degrees and ethylenically unsaturated carboxylic acids, which are obtained by condensing polyhydric alcohols and polybasic acids. (c) Polyurethane-based polyvinyl compound obtained by addition reaction of polyvalent isocyanate and hydroxyl group-containing ethylenically unsaturated monomer, (d) Hydroxyl group terminals of polyhydric alcohol and polybasic acid with various degrees of polymerization. A polyurethane-based polyvinyl compound obtained by an addition reaction of an ethylenically unsaturated monomer containing a hydroxyl group to an adduct of either an ester or a polyhydric alcohol and an excess equivalent of a polyvalent isocyanate, (e)
Examples include epoxy-based polyvalent vinyl compounds obtained by addition-reacting ethylenically unsaturated carboxylic acids to polyvalent epoxy resins. In the present invention, these compounds can be used alone or in combination of two or more. The photopolymerization sensitizer used in the present invention may be one that generates radicals when exposed to light, but typical examples include benzoin sensitizers such as benzoin methyl ether and benzoin butyl ether, and 2,4-di Ketone sensitizers such as ethoxyacetophenone, p-chlorobenzophenone, benzophenone, azobisisobutyronitrile, 2,
There are photopolymerization sensitizers such as azo compound sensitizers such as 2'-azobis-(2,4-dimethylvaleronitrile)azobenzene, and quinone sensitizers such as anthraquinone and phenanthraquinone. In the present invention, benzophenone-based photopolymerizable sensitizers are preferred from the viewpoint of adhesion to the substrate. In the present invention, the monofunctional acrylic monomer represented by general formula (B) includes, for example, diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, dibutylaminopropyl (meth)acrylate, Tertiary nitrogen atom-containing (meth)acrylic acid esters such as acrylate, dicyclohexylaminoethyl (meth)acrylate, etc., secondary nitrogen atoms such as tertiary butylaminoethyl (meth)acrylate, ethylaminoethyl (meth)acrylate, etc. Among them, tertiary nitrogen atom-containing (meth)acrylic esters are preferred from the viewpoint of adhesion to the substrate, and in particular, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (Meth)acrylate and the like are preferred. Typical ethylenically unsaturated monomers copolymerizable with (B) in the present invention include, for example, aliphatic or alicyclic alkyl esters of acrylic acid or methacrylic acid, where the alkyl group is, for example, a methyl group or an ethyl group. , n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, 2-ethylhexyl group, lauryl group, cyclohexyl group, and the like. Also included are aliphatic alkyl esters of dibasic unsaturated acids such as fumaric acid, maleic acid, and itaconic acid, and dialkyl esters having 1 to 4 carbon atoms in the aliphatic alkyl group. Typical examples of other copolymerizable ethylenically unsaturated monomers include aromatic vinyl compounds such as styrene and α-methylstyrene, (meth)acrylamide and (meth)acrylonitrile. Among these vinyl compounds, particularly in the present invention, alkyl esters of acrylic acid or methacrylic acid, particularly acyclic alkyl esters, are highly copolymerizable with the monomer (B) and copolymerizable with the compound (A) in the present invention. It is preferable from the viewpoint of compatibility with (C). In the present invention, in the copolymer (C) obtained by copolymerizing the monomers represented by the general formula (B), the copolymerization ratio of the monofunctional acrylic monomer (B) is 0.5% by weight.
The content is not less than 10% by weight, preferably not less than 2% by weight and not more than 8% by weight. When the acrylic monomer represented by the general formula (B) in the copolymer (C) is less than 0.5% by weight, the coating film cured by ultraviolet rays will not have sufficient adhesion to the substrate, resulting in the ultraviolet curable resin composition of the present invention. It cannot be used as an object. When the amount is more than 10% by weight, although the adhesion of the UV-cured coating film to the substrate is good, problems such as whitening of the cured coating film occur under high humidity. Cannot be used. In the present invention, the number average molecular weight of the copolymer (C) (value calculated in terms of polystyrene by gel permeation chromatography) is 1,000 or more and 10,000 or less. In particular, from the viewpoint of adhesion to the base material, those in the range of 2000 to 6000 are preferred. The number average molecular weight is
When it is smaller than 1000, the adhesion to the base material is poor. When the number average molecular weight is greater than 10,000, the compatibility with the compound (A) becomes poor and the adhesion to the substrate also becomes poor. In the present invention, the mixing ratio of compound (A) and copolymer (C) is in the range of 70/30<(A)/(C)≦95/5 by weight. When the copolymer (C) content is less than 5% by weight, the adhesion to the substrate is poor. Moreover, when the copolymer (C) is more than 30% by weight, although the adhesion is good, the cured coating film is not sufficiently crosslinked, and the chemical resistance and solvent resistance are poor, resulting in the UV curable resin composition of the present invention. It cannot be used as In the present invention, the copolymer (C) can be polymerized by various means and methods such as radical polymerization, ionic polymerization, solution polymerization, bulk polymerization, batch polymerization, continuous polymerization, etc. On the other hand, monomer charging methods include a batch method, a division method, a continuous method, and any one of the monofunctional unsaturated monomers represented by the general formula (B) and ethylenically unsaturated monomers copolymerizable therewith. A method in which the polymerization of a species or two species is preceded and the polymerization of the remaining monomer is delayed, etc.
Various combinations of these various means and methods can be arbitrarily adopted as desired, but in general, solution polymerization by radical polymerization using an azo initiator, a peroxide initiator, etc. However, control of the reaction is preferable in terms of versatility. The polymerization temperature at this time is usually desirably about 60°C to 150°C, and the polymerization may be carried out at a temperature selected depending on the raw material monomers and other auxiliary raw materials. Typical radical polymerization initiators used to obtain the copolymer (C) of the present invention by radical polymerization include peroxides such as benzoyl peroxide and methyl ethyl ketone peroxide; Examples of typical chain transfer agents include mercaptans such as mercaptoethanol and n-dodecylmercaptan. Typical polymerization solvents include, for example, toluene,
Examples include aromatic solvents such as xylene, alcohol solvents such as isopropyl alcohol, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl ethyl ketone. Next, various additives such as leveling agents, antifoaming agents, surfactants, various other auxiliary agents, organic solvents, etc. may be added to the ultraviolet curable resin composition of the present invention as necessary to improve workability. They can also be added for the purpose of adjusting the temperature, improving film properties, etc., as long as they do not impede the effects of the present invention. Next, any method can be used to form a film of the ultraviolet curable resin composition of the present invention on the base material, such as a method of dipping the base material, a method using a spray gun, a roll coater, a flow coater, etc. , a method using a gravure coater, etc. are typical. The ultraviolet light necessary for curing the ultraviolet curable resin composition of the present invention refers to photochemically active electromagnetic waves having a wavelength usually in the range of 200 nm to 500 nm. Sources of this ultraviolet light include carbon arc lamps, ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, ultraviolet fluorescent lamps,
Commonly used lamps such as xenon lamps can be used. The time required for irradiation depends on the type and content of the photosensitizer used in the ultraviolet curable resin composition,
Although it varies depending on 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 various conditions, it is possible to complete the process in a few seconds by adjusting these conditions. The ultraviolet curable resin composition of the present invention can be used as a base material for PET resins, such as transparent protective coats for film moldings, colored protective coats, and binders for printing inks. Next, the present invention will be explained with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples. In these, parts and proportions are by weight unless otherwise specified. Example 1 250 parts of toluene is charged into a flask equipped with a stirrer, a thermometer, a condenser, a dropping funnel, and a nitrogen gas blowing device at the top, and the temperature is raised to 90° C. while stirring and nitrogen gas blowing are continued. Then methyl methacrylate while keeping the temperature between 85°C and 90°C.
By dropping a mixture of 550 parts of butyl acrylate, 400 parts of diethylaminoethyl methacrylate, 50 parts of diethylaminoethyl methacrylate, and 40 parts of azobisisobutyronitrile from the dropping funnel over 3 hours, and continuing the reaction at the same temperature for 6 hours. An acrylic copolymer () with a number average molecular weight of 4000 and a non-volatile content of 80% was obtained.
Using this copolymer (2) as copolymer (C), an ultraviolet curable resin composition was produced with the following formulation. Copolymer () as 31.3 parts Compound (A) Orestar
A composition of the present invention was prepared by blending 50 parts of RA-1050 (manufactured by Mitsui Toatsu Chemical Co., Ltd., a polyester oligomer), 25 parts of neopentyl glycol diacrylate, and 3 parts of benzophenone as a photopolymerization sensitizer. The blending ratio of (A):(C) in this blend was 75:25. Next, the composition of the present invention was applied to a transparent polyester film (Lumirror #25, manufactured by Toray Industries, Inc.) with a thickness of 25 μm using a bar coater in an amount to give a coating film thickness of 20 g/m ² , and a commercially available high-pressure mercury lamp was used. (80W/cm) and height
It was cured by irradiating ultraviolet light for about 4 seconds from a position of 12 cm. The properties of this coating film are shown in Table 1. Example 2 Same as Example 1 except that a mixture of 600 parts of methyl methacrylate, 320 parts of ethyl acrylate, 80 parts of dimethylaminoethyl methacrylate, and 30 parts of azobisisobutyronitrile was used instead of the mixture of Example 1. A copolymer () with a number average molecular weight of 5500 and a non-volatile content of 80% was obtained. Using this copolymer (), a composition was produced with the following formulation. Copolymer () 18.75 parts Orester RA-1050 50.0 parts Neopentyl glycol diacrylate 35.0 parts Benzophenone 3.0 parts 106.75 parts The ratio of (A):(C) in this formulation was 85:15. This composition was cured by irradiating it with ultraviolet rays in the same manner as in Example 1. The properties of this coating film are shown in Table 1. Example 3 Same as Example 1 except that a mixture of 600 parts of methyl methacrylate, 380 parts of butyl acrylate, 20 parts of diethylaminoethyl methacrylate, and 50 parts of azobisisobutyronitrile was used instead of the mixture of Example 1. In the same manner, a copolymer () with a number average molecular weight of 2300 and a non-volatile content of 80% was obtained. A composition was produced using this copolymer () with the following formulation. Copolymer () 31.25 parts Orester RA-1050 50.0 parts Neopentyl glycol diacrylate 25.0 parts Benzophenone 3.0 parts 109.25 parts The ratio of (A):(C) in this formulation was 75:25. This composition was cured by irradiating it with ultraviolet rays in the same manner as in Example 1. The properties of this coating film are shown in Table 1. Example 4 In the same manner as in Example 1, an ultraviolet curable resin composition was manufactured using the following formulation. Copolymer () 8.75 parts Orester RA-1050 50.00 parts Neopentyl glycol diacrylate 43.00 parts Benzophenone 3.0 parts 104.75 parts The ratio of (A):(C) in this formulation was 93:7. This composition was cured by irradiating it with ultraviolet rays in the same manner as in Example 1. The properties of this coating film are shown in Table 1. Comparative Example 1 Same as Example 1 except that a mixture of 450 parts of methyl methacrylate, 400 parts of butyl acrylate, 150 parts of diethylaminoethyl methacrylate, and 40 parts of azobisisobutyronitrile was used instead of the mixture of Example 1. A acrylic copolymer () with a number average molecular weight of 3800 and a non-volatile content of 80% was obtained. A composition was prepared in the same manner as in Example 1 using this copolymer () instead of copolymer (). This composition was cured by irradiation with ultraviolet rays in the same manner as in Example 1. The properties of this coating film are shown in Table 1. Comparative Example 2 A mixture of 550 parts of methyl methacrylate, 450 parts of butyl acrylate, and 40 parts of azobisisobutyronitrile was used in place of the mixture of Example 1, but a number average molecular weight of 3600 was prepared in the same manner as in Example 1.
A copolymer () with a nonvolatile content of 80% was obtained. A composition was prepared in the same manner as in Example 1 using this copolymer () instead of copolymer (). This composition was cured by irradiation with ultraviolet rays in the same manner as in Example 1. The properties of this coating film are shown in Table 1. Comparative Example 3 A composition was manufactured with the following formulation. Olester RA-1050 50 parts Neopentyl glycol diacrylate 50 parts Benzophenone 3 parts 103 parts This composition was cured by irradiation with ultraviolet rays in the same manner as in Example 1. The properties of this coating film are shown in Table 1. Comparative Example 4 A composition was manufactured with the following formulation. Copolymer () 60.0 parts Olestar RA-1050 30.0 parts Neopentyl glycol diacrylate 22.0 parts Benzophenone 3.0 parts 115 parts This composition was cured by irradiation with ultraviolet rays in the same manner as in Example 1. The properties of this coating film are shown in Table 1. 【table】

Claims (1)

[Claims] 1. A mixture consisting of a compound (A) having at least one ethylenically unsaturated group in the molecule and a photopolymerizable sensitizer is applied to a base material, and a film is formed by irradiating the mixture with ultraviolet rays. In the ultraviolet curable resin composition for forming general formula (B) (In the formula, R ₁ is a hydrogen atom or a methyl group, R ₂ and R ₃ are each a hydrogen atom or an alkyl group, which are the same or different from each other, and n is an integer of 1 to 3.) 0.5% by weight of the acrylic monomer (B) or more, 10% by weight or less, and (B)
A copolymer (C) with a number average molecular weight of 1,000 to 10,000 obtained by copolymerizing an ethylenically unsaturated monomer copolymerizable with 90% to 99.5% by weight, 70/30<(A)/(C) )≦95/5 (weight ratio) An ultraviolet curable resin composition having improved adhesion to polyethylene terephthalate film.