JPS60248741A - Polyolefin molded article - Google Patents

Abstract

PURPOSE:To obtain a molded article having excellent offset printability and giving a uniformly printed product in high ink-adhesivity, by kneading a polyolefin with a polar polymer under heating, molding the obtained composition, and subjecting the molded article to corona discharge treatment. CONSTITUTION:100pts.(wt.) of a polyolefin is kneaded with 0.01-50pts., preferably 0.5-5pts. of a polar polymer under heating, and the molded article produced thereof is subjected to the corona discharge treatment. The polar polymer is e.g. an ethylenevinyl acetate copolymer, a vinyl chloride-vinyl acetate copolymer, etc. The corona discharge treatment is carried out preferably at a rate of 35-55 dyne/cm.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a polyolefin molded article with excellent offset printability.

(Prior Art) It is well known that polyolefins are inherently inert among various plastics and have poor surface properties such as durability, printability, and adhesiveness.

In order to improve these defects, polyolefin molded products are subjected to pretreatment such as acid treatment, flame treatment, and corona discharge treatment. It is possible to print with excellent printability without any unevenness, and also with good adhesion to the ink. However, in the case of offset printing, not only printing unevenness occurs, but also the adhesion to the ink is poor and the polyolefin molded product is printed before printing. had to do an anchor coat.

(Problems to be Solved by the Invention) Applying an anchor coat to a polyolefin molded product and performing offset printing on it provides good printability and no printing unevenness, and also has good adhesion with ink, but the anchor coat Doing so requires one more step and reduces work efficiency. or,
If more than two days have elapsed since anchor coating, the adhesion with the ink becomes extremely poor, resulting in poor working efficiency. In other words, more and more companies are working on two-day working days, and if you apply anchor coat the day before a holiday, if you print on the day after the holiday, you will only get a coat that has poor adhesion to the ink, and It was not possible to apply the anchor coat the day before, resulting in poor work efficiency.

(Means for solving the problems) The polyolefin molded product of the present invention has polyolefin 10
A molded article obtained by molding a polyolefin composition obtained by adding 001 to 50 parts by weight of a polar polymer to 0 parts by weight and heating and kneading the mixture is subjected to a corona discharge treatment.

In the present invention, polyolefins refer to those whose main components are polymers and copolymers of monoolefins such as ethylene and propylene butene, such as high-density polyethylene, medium-low density polyethylene, crystalline polypropylene, and crystalline ethylene-propylene block copolymers. Refers to polymers, polybutene, poly-3-methylbutene-1, poly-4-methylpentene-1, etc., and mixtures thereof.

The polar polymers used in the present invention include copolymers of ethylene and vinyl acetate, partially saponified copolymers of ethylene and vinyl acetate, copolymers of vinyl chloride and vinyl acetate, and copolymers of vinyl chloride and acrylic acid. , copolymers of fumaric acid, crotonic acid and their esters, copolymers of acrylonitrile and vinyl acetate, copolymers of ethylene and unsaturated acids or their esters, copolymers of ethylene and vinyl chloride copolymers of polypropylene and unsaturated acids or their esters; graft polymers of polyethylene and polypropylene with unsaturated acids or their esters; copolymers of ethylene or polypropylene with vinyl ether; copolymers of ethylene and styrene; Examples include copolymers, copolymers of ethylene and urethane, copolymers of ethylene and fluorine-containing monomers, chlorinated polyethylene, and chlorinated polypropylene.

The amount of the polar polymer used varies depending on the type thereof, but is 0.001 to 50 parts by weight, particularly preferably 2 to 10 parts by weight, based on 100 parts by weight of the polyolefin.

If the amount of the polar polymer is less than 0.001 parts by weight per 100 parts by weight of the polyolefin, no effect of improving the printability or adhesion with ink of the resulting polyolefin molding will be observed.

Moreover, if the amount is 50 parts by weight or more, the mechanical properties of the polyolefin molded product will be greatly deteriorated, which is undesirable.

The corona discharge treatment may be carried out by a commonly used corona discharge treatment, but it is preferable to carry out the entire corona discharge treatment at 35 to 55 dynθ/m.

In the present invention, an antistatic agent and a surfactant can also be used together with the polar polymer.

Usable antistatic agents include primary amine salts, tertiary amines, quaternary ammonium compounds, cationic antistatic agents such as pyridine derivatives, pre-sulfated, soap, nitrated ester oil, and sulfated Amide oil, sulfate ester salts, fatty alcohol, alkyl sulfate ester salt, fatty acid ethyl sulfonate, alkyl sulfonate, alkylnaphthalene sulfonate, alkylbenzene sulfonate, succinate sulfonate, phosphate ester salt, etc. Anionic antistatic agents, partial fatty acid esters of polyhydric alcohols, ethylene oxide adducts of fatty alcohols, ethylene oxide adducts of fatty acids, ethylene oxide adducts of fatty amines or fatty acid amides,
Ethylene oxide adducts of alkylphenols, ethylene oxide adducts of polyhydric alcohol moiety JJW fatty acid esters, nonionic antistatic agents such as polyethylene glycol, amphoteric antistatic agents such as carboxylic acid derivatives, imidacillin derivatives, etc. Can be mentioned.

The amount of antistatic agent used is 0.05 to 20 parts by weight, preferably 0.4 to 0.8 parts by weight, based on 100 parts by weight of the polyolefin. If it exceeds 2.0 parts by weight, the antistatic agent will bleed onto the surface of the polyolefin molded product, resulting in a total loss of appearance, which is not preferable.

Surfactants that can be used include polyoxyethylene glycol, polyoxypropylene glycol, polyoxypropylene triol, polyoxypropylene tetraol, condensates of ethylene oxide or propylene oxide and alkyl amines, and alkyl amides of ethylene oxide or propylene oxide. condensates of ethylene glycol, propylene glycol, or ethers or esters of polyethylene glycol or polypropylene glycol with trihydric or higher polyhydric alcohols or alkyl esters of polyhydric alcohols, etherified products of ethylene glycol, propylene glycol, or Derivatives of ethylene oxide and propylene oxide such as alkyl ethers, allyl ethers, alkyl allyl ethers and alkyl esters of polyethylene glycol and polypropylene glycol, glycol, glycerin,
Polyhydric alcohols such as polyglycerin, pentaerythritol, and sorbitol, fatty acid esters or heptathenic acid esters of polyhydric alcohols, and low molecular weight polyvinyl alcohols with a molecular weight of 10,000 or less.

Nonionic surfactants such as partial esterified products of low molecular weight polyvinyl alcohol, saturated fatty acids of 04 or more and less than 010, saturated or unsaturated fatty acids of 010 or more, saturated or unsaturated fatty acids of 08 or more, such as Li and Mg.

Anionic surfactants such as metal salts of higher fatty acids such as gold salts such as Oa%Zn and Ah, alkylaryl sulfonates such as alkylbenzene sulfonates, alkylphenol sulfonic acid groups, and alkylnaphthalene sulfonates can be used. .

The amount of the surfactant used is 01 to 10 parts by weight, preferably 05 to 5 parts by weight, per 100 parts by weight of the polyolefin. If the amount exceeds 10 parts by weight, the physical properties of the resulting polyolefin molded article will deteriorate and the surfactant will ooze out, which is undesirable.

The method for manufacturing polyolefin molded products of the present invention involves mixing polyolefin, polar polymer, antistatic agent, surfactant, coloring agent, etc. as necessary, in a mixing machine such as a drum laender, type blender, ribbon blender, etc. The mixture is premixed, heated and kneaded using a heating mixer such as an extruder, and then molded, followed by corona discharge treatment. Of course, polar, t"
Products subjected to corona discharge treatment are not excluded from the present invention. The temperature of the heating cross-wire must be above the melting and softening temperature of the polyolefin and below the decomposition temperature, but in particular the temperature needs to be above the melting and softening temperature of the polar polymer, and it is necessary that the polyolefin and polar polymer are kneaded uniformly. It is.

(Examples) Example 1 100 parts by weight of an ethylene-propylene block copolymer with a melt index of LO (manufactured by Chisso Petrochemical Co., Ltd.) and an ethylene-vinyl acetate copolymer with a vinyl acetate content of 20% (manufactured by Nippon Unicar) as a polar polymer. 5 parts by weight were mixed in a drum laender for 30 minutes, then melted and extruded in an extruder, sheeted to a thickness Q'15 mΔh width 300 m/ln, and at the same time, treated with a corona discharge treatment machine (manufactured by Kasuga Denki) to 38 dyne each. /cm ()OV, 22A)% 4
7dyns/crn (90V, X6A), 50dyne
1011 (110V, 5A), 54 dyne7
b (130v, a4A) to obtain a sheet-like molded polyolefin product.

Printability (printing unevenness and peeling test) using offset ink for the obtained sheet-shaped molded product.

Tensile strength, tear strength, flexural modulus, and low-temperature impact value were measured. The results are shown in the table.

The award, printing unevenness and peeling test were measured in the following manner using Daicure RT-7 (manufactured by Dainippon Ink & Chemicals Co., Ltd.) as an offset printing ink.

Printing unevenness test - Daicure R was applied to the obtained sheet-like molded product.
T-7i offset printing was performed, and ink coverage (printing unevenness) was evaluated using an R tester according to the following criteria.

Grade 5: A state in which 100% of the ink is on the printing surface.

Grade 4: A state in which 80-90% of the ink is on the printing surface.

Grade 3: A state in which 50% of the ink is on the printing surface.

Grade 2: A state in which 30% of the ink is on the printing surface.

Grade 1: Ink is not on the printing surface at all (0%)
Refers to the condition.

Peeling test: Daicure RT-
7i offset printing, temperature 20 C1 humidity 60
% atmosphere for 2 days, then I Wl/ on the printed surface.
Make incisions with a razor so that 100 squares are formed at ff1 intervals, then apply sellotape to this and quickly peel it off. Based on the number of squares that remain without peeling off, use the 9th standard. It was evaluated by

5th grade: 100 squares remaining 4th grade: 9
Level 3: 0 to 95 squares remaining...60 to 70
Grade 2: 30 to 50 squares remaining Grade 1: No squares remaining Example 2 As an antistatic agent in the formulation of Example 1 The same measurements as in Example 1 were carried out except that 0.8 parts by weight of polyoxyethylene alkylamine was added. The results are shown in the table.

Example 3 PEG-6000 (
The same measurements were carried out as in Example 1, except that 15 parts by weight of 15 parts by weight of Kogyo Urayaku Co., Ltd.) were added. The results are shown in the table.

Example 4 The same procedure as in Example 1 was carried out except that ethylene-methyl ethyl methacrylate copolymer was used as the polar polymer, and the same measurements were carried out. The results are shown in the table.

Example 5 Using beef tallow ethylene oxide adduct as an antistatic agent
The same procedure as in Example 4 was carried out except that the weight part was added, and the same measurements were carried out. The results are shown in the table.

Example 6 The same procedure as in Example 1 was carried out except that chlorinated polyethylene was used as the polar polymer, and the same measurements were carried out.

Example 7 The same procedure as in Example 6 was carried out except that 08 parts by weight of N-N-bis(2-hydroxyethyl)stearylamide was added as an antistatic agent, and the same measurements were carried out. The results are shown in the table.

Example Day The same procedure as in Example 6 was carried out, except that 5 parts by weight of stearin monoglyceride was added as a surfactant, and the same measurements were carried out. The results are shown in the table.

Example 9 The same procedure as in Example 1 was carried out except that an ethylene-acrylic acid copolymer was used as the polar polymer, and the same measurements were carried out. The results are shown in the table.

Example 1O Glycerin lanophosphate as an antistatic agent
The same procedure as in Example 9 was carried out except that the weight part was added, and the same measurements were carried out. The results are shown in the table.

Example 11 The same procedure as in Example 9 was carried out except that 5 parts by weight of polyoxystearylamide was added as a surfactant, and the same measurements were carried out. The results are shown in the table.

Comparative Examples 1 to 11 The same procedures as Examples 1 to 11 were carried out except that no corona discharge treatment was performed, and the same measurements were performed. The results are shown in the table.

Reference Example The same measurements as in Example 1 were carried out except that no polar polymer was added. The results are shown in the table.

(Effects) In the present invention, a specific amount of polar polymer gold is added to the polyolefin and subjected to corona discharge treatment, so it has good printability in offset printing, eliminates printing unevenness, and has good adhesion with printing ink. It is excellent. Polyolefins that have only been treated with corona discharge have poor adhesion with printing inks, and polyolefins that have only added polar polymers can improve offset printability depending on the type of polar polymer, but have poor adhesion with printing inks. It has poor adhesion.

Further, by adding an antistatic agent or a surfactant together with the polar polymer and performing a corona discharge treatment, offset printability and adhesion to printing ink can be further improved.

patent applicant

Claims (1)

[Claims] 00 parts by weight of polar polymer per 100 parts by weight of polyolefin
A polyolefin molded article obtained by subjecting a molded article obtained by molding a polyolefin composition obtained by adding 1 to 50 parts by weight and heating and kneading it to a corona discharge treatment.