JPH0441238A - Extrusion lamination method of thermoplastic resin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for extrusion lamination of thermoplastic resins, which makes it possible to produce a laminate with excellent adhesive strength to a base material.

[Conventional technology]

Conventionally, polyolefin resins such as polyethylene and polypropylene are extrusion laminated to base materials such as various resin films, aluminum foils, cellophane, paper, and cloth to impart heat-sealability, moisture resistance, etc. ,
These laminates are widely used as packaging materials for foods, release papers, adhesive tapes, and the like.

However, in order to reach a practical level of adhesive strength between the laminate layer and the base material in the laminate,
As a laminating method, the extruded resin temperature of the thermoplastic resin such as polyolefin resin which becomes the laminate layer is usually set to a high temperature of, for example, 310°C or higher, and the surface is oxidized in the space (so-called air gap) between the goo and the pressure roll. Furthermore, the surface of the base material is treated with a primer coat. Therefore, in the conventional extrusion lamination method, since the extrusion resin temperature is set to a high temperature, the non-adhesive surface of the laminate layer to the base material is also oxidized, resulting in a decrease in the heat sealability of the laminate and the need for an odor process. There are also problems with the complicated process and economic disadvantage.

In addition, a method has been proposed for improving the adhesive strength between the laminate layer and the base material in a laminate by treating an extruded molten film of thermoplastic resin with ozone (for example,
7-157724, etc.) has been put into practical use, but this method requires a primer coating treatment on the surface of the substrate and is effective in solving the former problem mentioned above.
The latter problem has not been resolved either.

[Problem to be solved by the invention]

The present invention was made to solve the above-mentioned problems in the conventional extrusion lamination method for thermoplastic resins, and therefore, even if the extrusion resin temperature of thermoplastic resins is lowered, the basic An object of the present invention is to provide a method for extrusion lamination of thermoplastic resins, which can produce a laminate with excellent adhesive strength to a base material without applying a primer coat treatment to the surface of the material.

[Means to solve the problem]

The extrusion lamination method of thermoplastic resin of the present invention will be described in detail below. A thermoplastic resin containing an isocyanate compound is extruded from a goo of an extruder at a resin temperature of 120 to 350°C to form a molten film, and then the molten film is It is characterized in that after being treated with ozone, the treated surface is used as an adhesive surface for pressure-bonding and lamination to a base material.

The thermoplastic resin in the present invention includes polyethylene,
Ethylene, such as copolymers of ethylene and α-olefins such as propylene, butene-1, and hexene-1; copolymers of ethylene and vinyl acetate, (meth)acrylic acid, (meth)acrylic acid esters, etc. resin, polypropylene,
Examples include polyolefin resins represented by propylene resins such as copolymers of propylene and α-olefins such as ethylene and butene-1, polyamide resins, saturated polyester resins, polystyrene resins, and polyvinyl chloride resins. Among these, polyolefin resins, particularly ethylene resins, are preferred.

In the present invention, it is essential that these thermoplastic resins contain an isocyanate compound.

Here, "thermoplastic resin containing an isocyanate compound" refers to a thermoplastic resin containing isocyanate groups (masked (including) exists.

Examples of the isocyanate compound include (a) monoisocyanate compounds such as phenyl isocyanate, 0-tolyl isocyanate, 0-chloroyl isocyanate, and α-naphthyl isocyanate, (b) hexamethylene diisocyanate, 26-dicyanate methyl caproate, 2
, 4- or 2.6-) lylene diisocyanate, 4,
4'-diphenylmethane diisocyanate, 3,3'-
dimethoxybiphenyl-4,4'-diisocyanate,
1,5-naphthylene diisocyanate, poly(methylene phenyl isocyanate) represented by the general formula
Di- and polyisocyanate compounds such as (c) (b)
NCO-terminated urethane prepolymers consisting of di- and polyisocyanate compounds and polyhydric alcohols such as ethylene glycol, propylene glycol, Examples include isocyanate compounds (a) to (c).

Among these, 4,4'-diphenylmethane diisocyanate, poly(methylene phenyl isocyanate), urethane prepolymers, and isocyanate compounds whose isocyanate groups are masked with phenol or amine are preferred.

The content of these incyanate compounds in the thermoplastic resin is 0.0003 to 5 in terms of incyanato groups.
% by weight, preferably from 0.001 to 1% by weight, particularly preferably from 0.0015 to 0.5% by weight. If the incyanate compound is not contained, the adhesive strength between the laminate layer and the base material as a laminate product will be poor.

As a method for blending an isocyanate compound into a thermoplastic resin, for example, a predetermined amount of a liquid, viscous, or solid isocyanate compound is added to a powder, pellet, or flake thermoplastic resin, and the mixture is added to a tumbler. , a ribbon blender, Henschel mixer, etc., and immediately or kneaded in an extruder and then fed to an extruder for extrusion lamination.Alternatively, a master batch containing an isocyanate compound prepared in the same manner is heated. A known method can be used, such as a method of feeding the material together with a plastic resin to an extruder for extrusion lamination.

In addition, thermoplastic resins contain additives such as slip agents, antistatic agents, antifogging agents, ultraviolet absorbers, and antioxidants, calcium carbonate, silica, and titanium oxide, to the extent that they do not interfere with the adhesion to the base material. , inorganic fillers such as talc, pigments, etc. can be added.

In the present invention, the resin temperature when extruding the thermoplastic resin from a die of an extruder to form a molten film is 120 to 350°C2, preferably 150 to 330°C1, particularly preferably 150 to 30°C.
00℃. If the resin temperature is less than 120°C, the spreadability of the resin will be poor and a molten film will not be obtained smoothly.
Adhesive strength to the base material becomes insufficient. Furthermore, if the temperature exceeds 350°C, problems such as a decrease in the heat sealability of the laminate and the generation of odor may occur, as well as problems such as the formation of gel-like substances, resulting in a decrease in mechanical strength and appearance. becomes.

Furthermore, in the present invention, it is essential to treat the adhesion surface of the molten film with the base material described below with ozone. Ozone treatment is performed by directing ozone-containing gas (air, etc.) from a nozzle or slit-shaped outlet toward the molten film surface, the substrate surface (described later), or the molten film from within the air gap. This is done by spraying toward the crimped area with the base material.

The ozone concentration in the sprayed gas is preferably 0.1 g/rr1 or more, more preferably Ig/rrf or more. Also, the amount of spraying is 0.01f relative to the width of the molten diluted film.
/min/1 or more is preferable, more preferably 0AII1
min/c11 or more. In this case, it should be avoided to increase the flow rate excessively because this will cause the molten film to oscillate and become uneven in thickness.

Next, the molten film treated with ozone by the method described above is guided to a pressure roll, and with the treated surface as an adhesive surface, it is pressure-bonded and laminated onto a base material that has also been guided to the pressure roll.

Substrates in the present invention include resin films or sheets made of polypropylene, polyamide, polyester, saponified products of ethylene-vinyl acetate copolymers, polystyrene, polyvinylidene chloride, polyvinyl alcohol, etc., metal foils or metal plates made of aluminum, iron, etc. , cellophane, paper, woven fabric, non-woven fabric, etc. are used, and the surface thereof is subjected to corona treatment, frame treatment, etc. as necessary.

The extrusion lamination method of the present invention can be applied to all cases in which a thermoplastic resin containing an isocyanate compound is extrusion laminated to a base material, and is applicable to all cases in which a thermoplastic resin containing an isocyanate compound is extrusion laminated on one side of the base material. , when two or more thermoplastic resins or two or more layers are sequentially extruded or coextruded laminated on one side of the base material using the thermoplastic resin on the base material side and another thermoplastic resin on the outside,
It is also effective when extrusion laminating the thermoplastic resin on both sides of a base material in the same manner, and when sandwich extrusion laminating the thermoplastic resin between two types of base materials.

The lamination speed in the extrusion lamination method of the present invention is approximately 10 to 400 m/min, and the thickness of the laminate layer is approximately 5 to 200 .mu.m.

〔Effect of the invention〕

Since the thermoplastic resin extrusion lamination method of the present invention has the above-described structure, even if the extrusion resin temperature of the thermoplastic resin is lowered than in the past, the base material can be laminated without applying a primer coat treatment to the surface of the base material. It is possible to produce laminates with excellent adhesive strength to materials.

〔Example〕

Example 1 Melt flow rate at 190°C 16 g/l 0 min,
High pressure polyethylene (LD) with a density of 0.919 g/cd
PE) 99% by weight, and poly(methylene phenyl isocyanate) (manufactured by Nippon Polyurethane Kogyo Co., Ltd., "Millionate MRJ, isocyanate group content 31% by weight)" 1
After mixing in a tumbler with 1% by weight of the isocyanate compound-containing resin masterbatch, which was previously blended with 1% by weight,
This mixture is extruded from a T-die attached to an extruder with a diameter of 90+ am at a resin temperature of 240° C. 1 for 500 sims to form a molten film, and then directed toward one side of the molten film at a position 30 m below the die. The installed nozzle with a width of 450s+a+ was processed. Next, using a known extrusion laminator,
A 15 μm thick nylon film was rolled out from the unrolling part, and the molten film was laminated with a pressure roll using the ozone treated surface as the adhesive surface. The lamination speed at this time was 80 m/min, and the thickness of the laminated layer was 30 μm.

Regarding the obtained laminate, the appearance of the laminate layer due to the generation of gel-like substances, the adhesive strength between the base material and the laminate layer, the heat-sealing strength after heat-sealing the laminate layers, and the temperature of the heat-sealed bag. Impact resistance strength was evaluated. The results are shown in Table-1.

Examples 2 to 5 The same procedure as in Example 1 was carried out except that the mixing proportions of the isocyanate compound-containing resin master C and 7 were set to 0.1% by weight, 0.5% by weight, 5% by weight, and 10% by weight. Extrusion laminated. The evaluation results are shown in Table-1.

Example 6 100% isocyanate compound blended resin masterbatch
Extrusion lamination was carried out in the same manner as in Example 1, except that the weight percent was bound. The evaluation results are shown in Table-1.

Comparative Example 1 Example 1 except that only high-pressure polyethylene was used without mixing the isocyanate compound-containing resin masterbatch.
Extrusion lamination was carried out in the same manner as above.

The evaluation results are shown in Table-1.

Comparative Example 2 Extrusion lamination was carried out in the same manner as in Example 1, except that the molten film was not subjected to ozone treatment. The evaluation results are shown in Table-1.

Example 7.8 Except that the extrusion resin temperature was 280°C1 and 300°C,
Extrusion lamination was carried out in the same manner as in Example 1.

The evaluation results are shown in Table-1.

Comparative Example 3 Example 8 except that the isocyanate compound-containing resin masterbatch was not mixed and only high-pressure polyethylene was used.
Extrusion lamination was carried out in the same manner as above.

The evaluation results are shown in Table-1.

Examples 9 to 11 Ethylene-vinyl acetate copolymer (EVA) with a melt flow rate of 15 g/10 min at 190°C, a vinyl acetate content of 10% by weight, and 5% by weight of silica with a diameter particle size of 2μ, Examples The same isocyanate compounds used in 1, each 1
% by weight, 5% by weight, and 15% by weight were mixed in a Henschel mixer, and each mixture was kneaded at 150° C. using an extruder, and then pelletized. Using each of these resins containing isocyanate compounds, extrusion lamination was carried out in the same manner as in Example 1, except that the extrusion resin temperature was 180''C and the thickness of the laminate layer was 40μ.

The evaluation results are shown in Table-1.

Comparative Example 4 Example 9 except that no isocyanate compound was blended
Extrusion lamination was carried out in the same manner as above. The evaluation results are shown in Table-1.

Example 12 The extrusion resin temperature was set to 320'C, and the adhesive surface with the laminate layer was previously subjected to corona discharge treatment (30W min/min) as a base material.
e) Extrusion lamination was carried out in the same manner as in Example 1, except that kraft paper with a basis weight of 75 g/n was used, the lamination speed was 300 m/min, and the thickness of the laminated layer was 15 μm. It is shown in Table 2.

Comparative Example 5 Example 1 except that only high-pressure polyethylene was used without mixing the isocyanate compound-containing resin masterbatch.
Extrusion lamination was carried out in the same manner as in 2. Table 2 shows the evaluation results.
Shown below.

Example 13 Extrusion lamination was carried out in the same manner as in Example 6, except that a staple woven fabric (vertical 80 pieces/25 m, width 75 pieces/25 s+111) was used as the base material, and the thickness of the laminate layer was 50 μm. The results are shown in Table-2.

Comparative Example 6 Extrusion lamination was carried out in the same manner as in Example 13, except that the molten film was not subjected to ozone treatment. The evaluation results are shown in Table-2.

Example 14 Resin masterbatch containing 90% by weight of propylene-ethylene random copolymer (PEC) with a melt flow rate of 35 g/10 min at 230°C and an ethylene content of 4% by weight, and the same isocyanate compound used in Example 1. 10% by weight were mixed in a tumbler, and this mixture was kneaded at 220°C using an extruder, and then pelletized. This pellet was fed to an extruder, and extrusion lamination was carried out in the same manner as in Example 1, except that the extrusion resin temperature was 280° C. and the base material was a 12 μm polyester film. The evaluation results are shown in Table-2.

Comparative Example Extrusion lamination was carried out in the same manner as in Example 14, except that the same high-pressure polyethylene used in Example 1 was used in place of the fincyanate compound-containing resin masterbatch.

The evaluation results are shown in Table-2.

(】) Adhesive strength ■ When the base material is a nylon film or a polyester film A test piece with a width of 15 mm and a length of 901 m1 was peeled from the base material and the laminate layer over a length of 40 am, and then
It is shown as the maximum value (g/15+++m) when T-shaped peeling is performed using a Schopper type tensile tester at a tensile speed of 300 (I1 m/min).

Note that the asterisk (*) in the evaluation results indicates that the laminate layer was broken.

(2) When the base material is kraft paper, air is introduced from the paper side using a bond tester (manufactured by Perkins), and the air pressure (kg/cd) is expressed when the base material and the laminate layer peel or break.

(2) When the base material is a double woven fabric, the test piece was rubbed by hand 10 times and the peeling state between the base material and the laminate layer was judged.

O: No peeling.

×: Peeled off.

(2) Heat sealing strength Seal the laminate layers of the laminate together using a hot plate heat sealer, sealing width 15, temperature 140°C, pressure 2 kg.
/c++], time 1 second Condition T: H-) A sealed test piece with a width of 15an and a length of 90am including the heat-sealed part was pulled at a tensile speed of 300m using a Schopper type tensile tester.
It is shown as the maximum value (kg/15 mm) when T-shaped peeling is performed at m/min.

(3) Impact resistance strength: Place the laminate layers of the laminate facing each other and heat-seal the three sides with a hot plate heat sealer (seal width 15m).
m, temperature 140" C1 pressure 2 kg/d, time 1 second) to produce a 150 mm x 150 nm (7) bag, and
After filling with 0cc of water, heat seal the remaining bag in the same way, and place a bag of the same size and weight of 1kg on top of that bag.
The falling height of the iron plate (cm) at which the heat-sealed part of the bag is destroyed by a single fall
) was sought.

Claims (1)

[Claims] A thermoplastic resin containing an isocyanate compound is extruded from a die of an extruder at a resin temperature of 120 to 350°C to form a molten film, and then the molten film is treated with ozone, and then the treated surface is used as an adhesive surface to pressure-bond and laminate to a base material. A thermoplastic resin extrusion lamination method characterized by: