JP2017007180A - Method for manufacturing laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a laminate containing no organic solvent, requiring no aging process and having a thickness similar to that of a laminate manufactured by a conventional dry lamination system.SOLUTION: A method for manufacturing a laminate is provided, including steps of: forming a solvent-free adhesive having a viscosity of 10000 to 500000 mPa s at a temperature of t°C into a melt film at a temperature of t°C and a speed of 20 to 300 m/min; drawing the melt film in a pre-solidification state; then disposing the drawn melt film on a substrate 1; then overlapping a substrate 2 on the melt film disposed on the substrate 1; and solidifying the adhesive layer to bond the substrates 1 and 2 by the adhesive layer having a thickness of 1 to 5 μm.SELECTED DRAWING: None

Description

  The present invention relates to a method for manufacturing a laminate. The laminate obtained by the present invention can be suitably used for a retort packaging material, a refill packaging material having content resistance, and a battery packaging material.

  For the formation of laminates for retort wrapping materials, refillable wrapping materials with resistance to physical properties, battery packaging materials, etc., conventionally, a dry laminating method using a solvent-type adhesive or an extensible method using a molten resin as an adhesive The rouge lamination method was adopted.

Patent Document 1 discloses a method for manufacturing an absorbent article, which uses a curtain coater and bonds a sheet and an elastic member with a hot melt adhesive.
Patent Document 2 discloses a corrugated cardboard manufacturing method characterized in that a hot melt adhesive is curtain coated to bond a core base paper and a liner.

JP-A-6-237957 JP-T-2006-519122

Since the dry laminating method includes an adhesive containing an organic solvent, an organic solvent recovery device and fire prevention equipment are required for use. In many cases, a curing agent is used, and “aging” for the curing requires several days.
On the other hand, the extrusion laminating method does not contain an organic solvent and uses a resin in a molten state, so there is no problem as described above. However, since the resin layer functioning as an adhesive is a thick film of 30 to 50 μm, it is a laminate. The total thickness also increases.
An object of the present invention is to produce a laminate that does not contain an organic solvent, does not require an aging process, and has a thickness comparable to that of a conventional dry laminate method.

The present inventors made a solvent-free adhesive exhibiting a viscosity of 10,000 to 500,000 mPa · s at a temperature t ° C. into a molten film at a temperature t ° C. and a speed of 20 to 300 m / min, and before solidification. After stretching the molten film, the stretched molten film is disposed on the base material 1, and then the base material 2 is stacked on the molten film disposed on the base material 1 to solidify the adhesive layer, It discovered that the said subject could be solved by bonding the said base materials 1 and 2 with the adhesive bond layer of 1-5 micrometers in thickness.
However, the above-mentioned t ° C. is an arbitrary temperature equal to or higher than the melting temperature of the solventless adhesive.

  The present invention has made it possible to produce a laminate that does not contain an organic solvent, does not require an aging process, and is as thin as the conventional dry laminate method.

A series of processes in which a solventless adhesive is melted, stretched, and the stretched molten film is disposed on the substrate 1 is similar to the process of applying the solventless adhesive on the substrate 1 in a molten state. It is also referred to as coating below.
The coating temperature t ° C., that is, the temperature t ° C. when the solventless adhesive is made into a molten film, is not particularly limited as long as it is higher than the melting temperature of the adhesive and lower than the decomposition temperature of the adhesive. .

  The viscosity of the coating is 10,000 to 50 at a temperature of t ° C. from the point that the solventless adhesive is melted, stretched and thinned, and the leveling property when it is disposed on the substrate 1. It is important to be 10,000 mPa · s.

The coating speed is important from 20 to 300 m / min. If it is 20 m / min or more, the productivity is high, and if it is 300 m / min or less, the leveling property to the substrate 1 is good, and the appearance after the substrate 2 is stacked and the adhesive layer is solidified is excellent.
The coating speed can be controlled by the conveyance speed of the substrate 1 described later.

  The curtain coater is a system in which melted adhesive is extruded from a plurality of slot-like nozzles and applied in a curtain-like flow.

  In order to stretch the molten film, a method using air pressure or any other appropriate method can be selected.

The solvent-free adhesive composition is preferably a polyester-based resin or an acid-modified polyolefin resin. Examples of the polybasic acid component of the polyester-based resin include isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, adipic acid, azelaic acid, Examples thereof include sebacic acid, succinic acid, glutaric acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, itaconic anhydride and ester compounds thereof. These can be used alone or in combination of two or more.
Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-butylene glycol, 1,4-cyclohexanedimethanol. , Trimethylolpropane, glycerin, 1,9-nanonediol, 3-methyl-1,5-pentanediol, polyether polyol, polycarbonate polyol, polyolefin polyol, acrylic polyol, polyurethane polyol, and the like. These can be used alone or in combination of two or more.

  In addition, a carboxyl group is formed in the molecule (inside the molecule or at the molecule end) obtained by further reacting the polyester-based resin with a polybasic acid such as phthalic acid, trimellitic acid, pyromellitic acid, or an anhydride thereof. It may be a polyester-based resin.

  Furthermore, the polyester-based resin is, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, hydrogenated. A polyester urethane resin obtained by reacting with a polyisocyanate such as diphenylmethane diisocyanate may also be used.

  The olefin component of the acid-modified polyolefin resin is an alkene having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, 1-hexene, (meth) acrylic acid ester component, etc. Can be given.

  Examples of the acid component include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid and the like, as well as unsaturated dicarboxylic acid half esters and half amides. Of these, maleic anhydride is preferred. The acid component may be copolymerized in the acid-modified polypropylene resin, and the form thereof is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (graft modification). ) And copolymerization by thermal degradation.

  The molten film may be a plurality of layers of two or more layers, and the molten films may be supplementarily crosslinked.

  The substrate 1 is selected from the group consisting of metal foils such as aluminum foil and SUS foil, silica-deposited films obtained by evaporating silicon oxide on plastic films, and alumina-deposited films obtained by evaporating alumina on plastic films. It is at least one kind, and the vapor deposition layer is disposed at least on the adhesive layer side. In addition, the metal foil surface and the vapor deposition surface may be subjected to known preservative treatments such as a phosphate chromate treatment, a chromate chromate treatment, a zinc phosphate treatment, a zirconium phosphate treatment, a titanium phosphate treatment, a hydrofluoric acid treatment, and a cerium treatment. In particular, a coating type antiseptic treatment in which an organic resin is contained in the preservative is particularly preferable.

  As the substrate 2, stretched film made of polyamide or polyester, unstretched made of at least one kind of thermoplastic resin selected from the group consisting of polyethylene, polypropylene, olefin copolymers, these acid-modified products and ionomers A film is preferred. Moreover, you may use the film by which the component bridge | crosslinked with a hydroxyl group or carboxylic anhydride was previously coated.

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the examples and comparative examples,% means mass%.
(Synthesis Example 1)
In a four-necked flask, 20.5 parts ethylene glycol, 45.8 parts neopentyl glycol, 38.9 parts 1,6-hexanediol, 61.4 parts isophthalic acid, 61.4 parts terephthalic acid, 50. sebacic acid. 5 parts and 1.2 parts of benzoic acid were charged, dehydrated and condensed by heating to 240 ° C. while stirring under a nitrogen stream, and the reaction was continued until the acid value was 5 or less. The reaction was continued at 1 mmHg or less under reduced pressure, and excess alcohol was distilled off to obtain a polyester resin.

  300 g of the polyester resin was heated with stirring under a nitrogen stream, and 3 g of isophorone diisocyanate was added in an atmosphere at 150 ° C., and stirring was continued. Stirring was continued until absorption derived from unreacted NCO groups disappeared by IR analysis to obtain a urethane-modified polyester resin.

  300 g of the urethane-modified polyester resin is charged into a four-necked flask, heated to 180 ° C. while stirring in a nitrogen stream, charged with 4 g of ethylene glycol bisanhydrotritate and 2 g of trimellitic anhydride, and at 180 ° C. for 1 hour. An acid-modified polyester resin (A-1) was obtained by holding and modifying 36% of the hydroxyl groups in the urethane-modified polyester alcohol (calculated from the blending ratio) with an acid. The melt viscosity at 110 ° C. was 80,000 mPa · s.

  The melt viscosity was measured using a cone plate viscometer at a temperature at which a 100 poise cone was rotated at 30 rpm and the adhesive could be melted.

(Synthesis Example 2)
100 parts of polypropylene are charged with 20 parts of maleic anhydride and 375 parts of xylene in a three-necked flask equipped with a nitrogen inlet, a thermometer and a stirring rod, and heated to 130 ° C. with stirring in a nitrogen gas atmosphere. 0.1 part benzoyl peroxide is dissolved in 40 parts xylene and added dropwise over 90 minutes. After completion of dropping, heating and stirring are continued at 130 ° C. for 60 minutes. After 60 minutes, cool to room temperature. The obtained suspension was filtered to remove xylene, and then washed with methyl ethyl ketone 2 to 3 times to obtain a polypropylene-maleic anhydride copolymer resin (maleic anhydride graft ratio 0.6%). (A-2). The melt viscosity at 190 ° C. was 420,000 mPa · s.

(Synthesis Example 3)
A four-necked flask is charged with 83.2 g of isophthalic acid, 83.2 g of terephthalic acid, 99.8 g of ethylene glycol, and 71.8 g of neopentyl glycol, and subjected to an esterification reaction at 200 to 220 ° C. for 8 hours. After distilling off, 188 g of azelaic acid was added, and the esterification reaction was further carried out for 4 hours. After distilling a predetermined amount of water, 0.13 g of tetraisobutyl titanate was added, the pressure was gradually reduced, and a transesterification reaction was performed at 1.3 to 2.7 hPa and 230 to 250 ° C. for 3 hours to obtain a polyester resin (B -2) was obtained. The melt viscosity at 130 ° C. was 850,000 mPa · s.

Example 1
Using acid-modified polyester resin (A-1) as a solvent-free adhesive, create a molten film under conditions of temperature 110 ° C., viscosity 80,000 mPa · s, speed 100 m / min, and melt film up to 3 μm It was stretched and placed on aluminum foil. Next, an unstretched polypropylene film was stacked on the stretched melt film, the melt film was solidified to form an adhesive layer, and both substrates were bonded to obtain a laminate.

(Example 2)
Using acid-modified polyolefin resin (A-2) as a solvent-free adhesive, create a molten film at a temperature of 190 ° C., a viscosity of 420,000 mPa · s, and a speed of 100 m / min. It was stretched and placed on aluminum foil. Next, an unstretched polypropylene film was stacked on the stretched melt film, the melt film was solidified to form an adhesive layer, and both substrates were bonded to obtain a laminate.

(Comparative Example 1)
Using polyester-based resin (B-1) as a solvent-free adhesive, a molten film was created under conditions of a temperature of 130 ° C., a viscosity of 850,000 mPa · s, and a speed of 100 m / min, and the molten film was stretched to 3 μm. Arranged on aluminum foil. Next, an unstretched polypropylene film was stacked on the stretched melt film, the melt film was solidified to form an adhesive layer, and both substrates were bonded to obtain a laminate.

The state of the adhesive layer was visually evaluated from the unstretched polypropylene film side with respect to the laminate obtained as described above.
○: Adhesive layer is uniform and appearance is good ×: Adhesive layer is uneven and appearance is poor

  From the results shown in Table 1, the acid-modified polyester resin having a viscosity of 80,000 mPa · s at a temperature of 110 ° C. has excellent elasticity that can withstand a stretching stress at a temperature of 110 ° C. You can see that it has physical properties. Similarly, an acid-modified polyolefin resin having a coating viscosity of 420,000 mPa · s at a temperature of 190 ° C. is balanced between elasticity and extensibility.

  On the other hand, since the polyester resin having a coating viscosity of 850,000 mPa · s at a temperature of 130 ° C., which is Comparative Example 1, has a high viscosity, it has a low stretching stress at a temperature of 130 ° C. Resulting in. When the temperature is raised to lower the melt viscosity, hydrolysis of the ester bond starts and the adhesive performance is lowered.

  According to the production method of the present invention, since a solventless adhesive is used, it is not necessary to install a special solvent recovery device, and a two-component solventless adhesive that requires an aging process using a main agent and a curing agent. On the other hand, it is possible to cope with a short delivery time by not requiring an aging process.

Claims (5)

  A solventless adhesive exhibiting a viscosity of 10,000 to 500,000 mPa · s at a temperature of t ° C. is melted at a temperature of t ° C. and a speed of 20 to 300 m / min, and the molten film is formed in a state before solidification. After stretching, the stretched molten film is disposed on the substrate 1, and then the substrate 2 is stacked on the molten film disposed on the substrate 1, and the adhesive layer is solidified to have a thickness of 1 to 5 μm. A method for producing a laminate, in which the substrates 1 and 2 are bonded together with an adhesive layer (provided that t ° C. is an arbitrary temperature equal to or higher than the melting temperature of the solventless adhesive).   The manufacturing method of the laminated body of Claim 1 which makes a solvent-free-type adhesive a molten film with a curtain coater.   The manufacturing method of the laminated body of Claim 1 or 2 with which a solventless type adhesive agent contains a polyester-type resin.   The substrate 1 is at least one selected from the group consisting of an aluminum foil, a SUS foil, a silica-deposited film obtained by depositing silicon oxide on a plastic film, and an alumina-deposited film obtained by depositing alumina on a plastic film. Item 4. A method for producing a laminate according to Item 3.   The method for producing a laminate according to claim 1 or 2, wherein the solventless adhesive contains an acid-modified polyolefin, the substrate 1 is an aluminum foil, and the substrate 2 is an unstretched film of a thermoplastic resin.