JPS6056178B2 - Coated molded products of polyethylene or ethylene copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyethylene (hereinafter abbreviated as PE) coated with polyurethane paint.

), ethylene ethyl acrylate copolymer (hereinafter referred to as EEA)
It is abbreviated as ) or ethylene vinyl acetate copolymer (hereinafter referred to as EV
Abbreviated as A. ) Regarding molded products. For more details, please refer to P.E., E.
-1- Base resin, aliphatic hydrocarbon resin, selected from the group consisting of polybutadiene, carboxylated ethylene copolymer, EVA, chloroprene rubber and styrene-butadiene block copolymer, on a base material made of EA or EVA. A primer layer is formed from a mixture of an aromatic aliphatic copolymer resin, rosin, and one or more tackifying resins selected from the group consisting of rosin derivatives, and a polyurethane coating is formed on the top surface of the primer layer. Polyethylene, EEA or E
This relates to VA painted moldings.

Generally, it is extremely difficult to perform secondary processing such as painting or printing on PE or ethylene copolymer molded products.

Therefore, conventionally, pigments were kneaded into PE or ethylene copolymer to color the PE or ethylene copolymer prior to molding. However, this method has the disadvantage that it is difficult to make subtle adjustments to the color tone.

As a method for improving the secondary processability of PE or ethylene copolymer molded products, chemical etching treatment,
It has been proposed to perform surface treatments such as corona discharge treatment, flame treatment, and plasma jet treatment. Although I am calm,
Such surface treatment methods have various drawbacks, such as requiring expensive equipment and complicated processes, limiting the shape and size of molded products that can be treated, and making uniform treatment difficult. , has hardly been put into practical use.

Furthermore, a method is known in which a polyolefin molded product is treated with a halogenated hydrocarbon solution or suspension of rubber or an addition-polymerized resin having a polar group, and then coated with an acrylic resin paint.

However, this method uses 99% of toxic halogenated hydrocarbon solution.
It must be heated to around 0°C, which is not sanitary.

Furthermore, the adhesion of the coating film cannot be said to be perfect. Therefore, the present inventors, in an attempt to overcome the above-mentioned drawbacks of the prior art, have conducted extensive research in order to develop a primer with good adhesion for painting and printing on PE and ethylene copolymer molded products.

As a result, at least one polymer selected from polybutadiene, carboxylated ethylene copolymer, EVA, chloroprene rubber, and styrene-butadiene block copolymer, aromatic hydrocarbon resin, aliphatic hydrocarbon resin,
It has been discovered that the desired primer can be obtained by dissolving an aromatic aliphatic copolymer resin, rosin, and one or more tackifying resins among rosin derivatives in a solvent,
The present invention has now been completed. The primer of the present invention is P
It has good paintability and printability not only for E-molded products but also for ethylene copolymer molded products such as EVA and EEA, has an extremely wide coating range, and is characterized by not using toxic halogenated hydrocarbons. It is.

Furthermore, the primer of the present invention contains 5% or more of PE and ethylene copolymer in a mixture of PE and ethylene copolymer and thermoplastic rubber such as styrene-butadiene block copolymer, ethylene propylene rubber, and polybutadiene. It also has good paintability and printability for molded products of the mixture.

The PE used as the base material of the molded product of the present invention has a low density V
Either E or high-density PE may be used, but low-density PE is preferable from the viewpoint of adhesion.

The EVA used as the base material for the molded product of the present invention is JI
Melt index by SK673O! 0.1-3
00'/1 Gin, the vinyl acetate content according to JIS K673O is 1 to 5% by weight. The EEA used as the base material for the molded product of the present invention has a melt index of 0.1 to 300 y/1 powder according to ASTM D-1238, and an ethyl acrylate content of .1 to 5 mass %.

There are various molded products using these PE and ethylene copolymers.

These molded products are manufactured by injection methods, press methods, blow molding methods, extrusion molding methods, powder molding methods, and the like. Examples of the polymer forming the primer used in the present invention include polybutadiene, carboxylated ethylene copolymer, chloroprene rubber, EVA, and styrene-butadiene block copolymer.

Specifically, the following are preferably used. That is, polybutadiene has a Mooney viscosity of ML. Polybutadiene rubber with l+4100℃ of 10-200, melt flow index (150℃, 2160f) according to ASTM Dl238 of 0.1
~500'/1 syndiotactic 1,2-polybutadiene resin, carboxylated ethylene copolymer, EVA, acrylic acid, maleic anhydride, etc.
β-unsaturated carboxylic acid and/or its anhydride; show.

) is obtained by copolymerizing at least one vinylidene monomer having JISKOO7O-
66 acid value is 1-500Tn9K0H/y polymer, JISK673O melt index is 0.1-500
500y/10min, chloroprene rubber is normal chloroprene rubber and copolymer of chloroprene, styrene, isoprene, acrylonitrile, etc. with Mooney viscosity ■7, +4100℃ is 10-200, EVA
As for the styrene-butadiene block copolymer, the melt index according to JIS K673O is 10 to 600y/10 minutes, the vinyl acetate content is 20 to 20% by weight according to JIS K673O, and the melt index condition G according to ASTM Dl238 (2 (1) ° C. ,5kg)
is 0 to 50y/10 minutes.

Examples of the adhesive resin forming the primer used in the present invention include aromatic hydrocarbon resins, aliphatic hydrocarbon resins, aromatic aliphatic copolymer resins, rosin, and rosin derivatives.

The aromatic hydrocarbon resin is a petroleum resin obtained by polymerizing aromatic olefins and diolefins of the C9 fraction of petroleum.

The aliphatic hydrocarbon resin is a petroleum resin obtained by polymerizing aliphatic olefins and diolefins of the Q fraction of petroleum.

The aromatic aliphatic copolymer resin is a petroleum resin obtained by copolymerizing aliphatic olefins and diolefins from the q fraction of petroleum and C, and aromatic olefins and diolefins from the q fraction of petroleum.

Rosin includes gum rosin, tall oil rosin, and wood rosin. Rosin derivatives are rosin modified products such as hydrogenated rosin, polymerized rosin, rosin polyol ester, disproportionated rosin, hydrogenated rosin polyol ester, and polymerized rosin polyol ester. The ratio of the polymer forming the primer and the tackifying resin is 50 to 9% by weight of the polymer, preferably 65 to 75% by weight, and 10 to 5% by weight of the tackifying resin, preferably 25% by weight. ~35% by weight is suitable.

If the amount of the high molecular weight polymer exceeds 9% by weight or is less than 5% by weight, adhesion to PE will be lost, which is undesirable. If necessary, an antistatic agent may be added to the primer in order to prevent the adhesion of dust during coating due to static electricity of PE and ethylene copolymer. Furthermore, in order to improve the heat resistance of the primer, if necessary, a high molecular weight polymer and/or
Or organic peroxides that can cross-link tackifying resins, fillers to reduce the price of primers, increase viscosity, etc.
A silane-based, titanium-based, or chromium-based coupling agent may be added for the purpose of improving the adhesion of the primer.

There are various methods for forming a primer layer on PE and ethylene copolymer, such as heating and melting the primer and applying it using a hot melt applicator, or emulsifying the primer and applying it by brushing, spraying, etc. There are several methods, but the common method is to dissolve the primer in a solvent and apply it by brushing, spraying, etc.

The solvent for dissolving the primer does not need to be specified as long as it dissolves the polymer and adhesive resin forming the primer, but toluene, xylene, mineral spirits, etc. It is preferable from the viewpoint of solubility in resin and economical efficiency.

Next, the polyurethane paint may be one-pack type, two-pack type, room temperature curing type, or heat curing type, but it is not preferable to use one that is so hard that it cannot keep up with the flexibility of PE and ethylene copolymer.

In addition, in the case of a heat-curing type, one that hardens at a temperature of 70 to 90°C or lower is preferable since there is a limit to the heat resistance of PE and ethylene copolymers. The thickness of the primer layer in the present invention is suitably 0.5 to 50 y/mm, preferably 2 to 20 y/mm.

If the coating amount of the primer is less than 0.5 y/y, the strength of the primer film will be weak and it will be difficult to apply the primer uniformly, so the adhesion with PE, ethylene copolymer and polyurethane paints will tend to deteriorate. It is from. Furthermore, if the amount of primer applied exceeds 50 y/d, it may be difficult to apply the primer uniformly due to the increased viscosity of the primer when applying the primer by brushing, spray painting, etc. PE and ethylene copolymer molded products treated with the primer of the present invention and urethane coated have excellent adhesion to PE and ethylene copolymer molded products, have good gloss, and have a beautiful appearance.

In addition, PE and ethylene copolymer molded products coated with urethane are suitable for use as automobile parts such as pumper sites and mudguard sheets, miscellaneous goods, indoor and outdoor parts, materials for hard gear, leisure goods, etc. . Examples of manufacturing the molded product of the present invention are shown below as examples. Example 1 EVA (melt index 75 Da/10 minutes, vinyl acetate content 4%, trade name Ultrasen 760, manufactured by Toyo Soda Kogyo Co., Ltd.) 7y and aromatic aliphatic copolymer resin (trade name Toho Hi Resin) 90 Toho Oil Resin Co., Ltd.) 3f
was dissolved in 90f toluene and used as a primer.

Low-density PE injection molded plate treated with this primer with toluene, 2 Ugly 00m x 0 pieces (Melt index 15)
g/10 min, density 0.918, trade name Petrolosene 35
0, Toyo Soda Kogyo Co., Ltd.) and EVA injection molded plate 2?
×10"×15" (melt index 7f/l powder, vinyl acetate content 6% by weight, product name Ultrasen KanG manufactured by Toyo Soda Kogyo Co., Ltd.) and EEA breath molding plate 2wRx10
0rIn×10- (melt index 13y/10 min, ethyl acrylate content 8% by weight, product name DPDJ-
8026 (manufactured by Nippon Unicar Co., Ltd.) and dried in two batches at 70C.

When the coating thickness of the primer was measured after drying, it was 5y/R.
It was ft. Next, we applied a two-component thermosetting urethane paint (base agent: EURAK B-2375U, curing agent: EURAK PU-6).
14, manufactured by Hirono Chemical Industry Co., Ltd. (30 parts by weight of curing agent per 100 parts by weight of main agent) was spray coated and dried at room temperature.

After drying, heat cure at 70℃ for 4 hours to obtain JISDO2O2
, a goban test using 8 tears was conducted. The results are shown in Table 1. Example 2 Stem ethylene vinyl acetate copolymer obtained by copolymerizing vinyl chloride/maleic anhydride/acrylic acid in the presence of EVA (melt index 30y/10min, vinyl acetate content 3% by weight) Melt index cutting 1'/10 minutes consisting of 85% by weight component and 2% by weight vinyl chloride component, carboxylated ethylene copolymer 7f with acid value 42m9K0H/f and aromatic aliphatic copolymer resin (trade name: Toho Hi Resin) 90 (manufactured by Toho Oil Resin Co., Ltd.) 3y was dissolved in 90y of toluene and 100y of xylene to prepare a primer.

High-density PE injection molded plate 2T1n x 100Ts treated with this primer with toluene! t×150 pieces (melt index 13'/10 minutes, density 0.957, trade name Chubu Polyethylene 2000, manufactured by Chubu Chemical Co., Ltd.) and E
VA extrusion molded plate 1 block x 100m x 100TIrIt (melt index 1.5y/1 powder, vinyl acetate content 2%, trade name Ultrasen 631, Toyo Soda Kogyo Co., Ltd.)
) and EE8 injection molded plate 2wnXI00m×100T
n (melt index 20y/1 powder, ethyl acrylate content 18% by weight, trade name DPDJ-9169, manufactured by Nippon Unicar Co., Ltd.) was spray coated, and the two powders were dried in 7 (generations). After drying, the coating thickness of the primer was measured and found to be 15V/. It was d. Next, urethane coating was applied in the same manner as in Example 1, and after heating and curing, JlSDO2O
A cross-cut test was conducted according to 2.

The results are shown in Table 1. Example 3 Syndiotactic 1,2-polybutadiene resin (melt index 3f/1 powder, trade name JSRRB81O
, manufactured by Japan Synthetic Rubber Co., Ltd.) 6f and aromatic hydrocarbon resin (product name: Vetcol F-110, manufactured by Toyo Soda Kogyo Co., Ltd.)
(manufactured by Arakawa Chemical Co., Ltd.) 2f and hydrogenated rosin glycerin ester (trade name: Ester Gum H, manufactured by Arakawa Chemical Co., Ltd.) 2y were dissolved in 90y of toluene to prepare a primer.

This primer was coated with the same high-density PE and EVA as in Example 2.
, EEA molded plate was brushed and dried for 20 minutes in step 7. After drying, the coating thickness of the primer was measured and was 20 f.
It was 1/A. Next, urethane coating was applied in the same manner as in Example 1, and after curing by heating, a cross-cut test according to JISDO2O2 was conducted.

The results are shown in Table 1. Example 4 Chloroprene rubber (Mooney viscosity MLl+, 100°C 5
0, Product name Skyplane R-22, Toyo Soda Kogyo Co., Ltd.
) 7y, an aromatic aliphatic copolymer resin (trade name: Toho Hiresin 90, manufactured by Toho Oil Resin Co., Ltd.) 2y, and gum rosin 1V were dissolved in 90f of toluene to prepare a primer.

This primer was mixed with the same low density PE and EVA as in Example 1.
, EEA molded plate was brushed and dried at 70°C. After drying, the coating thickness of the primer was measured and was 20y/
It was ai. Next, urethane coating was applied in the same manner as in Example 1, and after curing by heating, a cross-cut test was conducted using JISDO2O2.

The results are shown in Table 1. Example 5 EVA (melt index 400y/1 powder, vinyl acetate content 2%, trade name Ultrasen 722, manufactured by Toyo Soda Kogyo Co., Ltd.) 7y and aromatic aliphatic copolymer resin (trade name Toho Hi Resin 90) ) 2y and hydrogenated rosin pentaerythritol ester (trade name: Ester Gum HP, manufactured by Arakawa Chemical Co., Ltd.) 1y were dissolved in 90y of toluene and 100y of xylene to prepare a primer.

This primer was coated with the same high-density PE and EVA as in Example 2.
, was spray-painted on an EEA molded plate and dried at 70°C. When the coating thickness of the primer was measured after drying, it was 10.
It was y/d. Next, in the same manner as in Example 1, urethane coating was applied and cured by heating, followed by a cross-cut test using JISDO2O2. The results are shown in Table 1. Comparative Example 1 The urethane paint of Example 1 was applied directly to the low-density PE, EVA, and EEA of Example 1 without a primer and cured by heating, and then a cross-cut test according to JIS DO2O2 was conducted.

The results are shown in Table 1. Comparative Example 2 EVA (melt index 75y/10 min, vinyl acetate content 4%, product name Ultrasen 760, manufactured by Toyo Soda Kogyo Co., Ltd.) 7y and Tempel resin (product name YS Resin PX-1150, Yasushi Oil Industry Co., Ltd.) 3y (manufactured by Co., Ltd.) was dissolved in 90y of toluene to prepare a primer.

This primer was applied to the low density PE of Example 1 in the same manner as in Example 1. Next, urethane coating was applied in the same manner as in Example 1, and after curing by heating, a cross-cut test was conducted using JISDO2O2.

The results are shown in Table 1. Comparative Example 3 EVA7q and α-methylstyrene vinyltoluene copolymer of Comparative Example 2 (trade name: Picotex LC, Etsuo Chemical Co., Ltd.)
Co., Ltd.) 3y was dissolved in 90f of toluene to prepare a primer.

This primer was applied to the high density PE of Example 2 in the same manner as in Example 1. Next, in the same manner as in Example 1, urethane coating was applied and cured by heating, followed by a cross-cut test using JISDO2O2.

The results are shown in Table 1. Comparative Example 4 9.5 y of chloroprene rubber and 0.5 y of aromatic aliphatic copolymer resin of Example 4 were dissolved in 90 y of toluene to prepare a primer.

This primer was applied to the low density PE of Example 1 in the same manner as in Example 4. Next, urethane coating was applied in the same manner as in Example 1, and after curing by heating, a cross-cut test was conducted using JISDO2O2.

The results are shown in Table 1. Comparative Example 5 Syndiotactic 1,2-polybutadiene resin 1y and aromatic hydrocarbon resin 9y of Example 3 were dissolved in 90 Da of toluene to prepare a primer.

This primer was used as the high-density primer of Example 2? E was coated in the same manner as in Example 2. Next, apply urethane coating as in Example 1,
After heating and curing, a cross-cut test was conducted according to JISDO2O2.

The results are shown in Table 1. Example 6 Styrene-butadiene block copolymer (trade name: Cariflex TR-1102, manufactured by Shell Chemical Co., Ltd.) 7y and aliphatic petroleum resin (trade name: Escorets 131, manufactured by Hetsuso Chemical Co., Ltd.) 3y were dissolved in 99y of toluene. It was dissolved and used as a primer.

This primer was mixed with the same low density PE as in Example 1. ．． EV
A. ．． The EEA molded plate was brushed and dried at 70°C for 20 minutes.

After drying, the coating thickness of the primer was measured and found to be 10y/a. Next, urethane coating was applied in the same manner as in Example 1, and after curing by heating, a cross-cut test was conducted using JISDO2O2.

The results are shown in Table 1. -Note: The test methods in Examples and Comparative Examples are as follows.

Eye test: JISDO2O28. ll. A/100 depending on l type
A indicates the number of remaining coating films.

Claims (1)

[Claims] 1 A group consisting of polybutadiene, carboxylated ethylene copolymer, ethylene vinyl acetate copolymer, chloroprene rubber, and styrene-butadiene block copolymer on a base material consisting of polyethylene, ethylene ethyl acrylate copolymer, or ethylene vinyl acetate copolymer 50 to 90% by weight of one or more selected polymers and one or more tackifying resins selected from the group consisting of aromatic hydrocarbon resins, aliphatic hydrocarbon resins, rosin, and rosin derivatives. A polyethylene or ethylene copolymer coated molded product comprising a primer layer of 0.5 to 50 g/m^2 consisting of ~50% by weight, and a polyurethane coating film formed on the upper surface thereof.