JPH08244127A - Production of laminate - Google Patents

Abstract

PURPOSE: To obtain a laminate without using an adhesive without being restricted too much by processing temp. or a processing speed by applying surface oxidizing treatment to a nonwoven fabric and extruding an extrusion laminating resin in a molten state at specific temp. to form a film and treating the surface of the film with ozone before bonding the film to the oxidizing treatment surface of the nonwoven fabric under pressure. CONSTITUTION: Surface oxidizing treatment is applied to at least one surface of a nonwoven fabric and an extrusion laminating resin is extruded in a molten state while the resin temp. just under a die is set to 180-340 deg.C to form a film and at least one surface of the film is treated with ozone. These treated surfaces are brought to a contact state to bond the film and the nonwoven fabric under pressure. For example, when the surface oxidizing treatment of the nonwoven fabric is performed by corona discharge, corona discharge density is set to 5w.min/m<2> or more. In the ozone treatment of the extrusion laminating resin, for example, ozone-containing air is continuously sprayed on the molten film from the blowoff orifices of the nozzles provided to the air gap under the die.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminate by extrusion laminating a nonwoven fabric. More specifically, extrusion laminate, which is one type selected from the group consisting of polyethylene-based resins, polypropylene-based resins, ethylene-vinyl ester-based copolymer resins and ethylene- (meth) acrylic acid ester-based copolymer resins, for nonwoven fabrics. Manufacture of a laminate in which strong adhesion can be obtained without using an adhesive such as an anchor coating agent when the resin for extrusion is extrusion-coated to produce a laminate, and the adhesive strength can be controlled if necessary. It is about the method.

Properties which cannot be possessed by adhering a film-shaped molded product such as plastic to a non-woven fabric, for example,
It is common practice to produce a laminate that has heat sealability, gas barrier properties, water resistance, moisture resistance, smoothness, etc., and the products thus obtained are used for clothing, daily life materials,
Widely used for medical hygiene and industrial materials.

As a method for producing a laminate with a non-woven fabric by such film lamination processing, there are, for example, an extrusion laminating method, a dry laminating method, a wet laminating method, a hot melt laminating method, a powder laminating method and a film transfer method. Although these are subjected to the most suitable processing method according to their final use, the extrusion laminating method is widely used because of its cost advantage.

As the polyolefin resin coated by the extrusion laminating method, for example, polyethylene, polypropylene, ethylene copolymer and the like are generally used, and one layer or two or more layers are extrusion coated. Among them, polyethylene is widely and widely used.

In the extrusion laminating method, the adhesive strength varies greatly depending on the type of the nonwoven fabric, the constituent materials, etc., so that it is necessary to pay sufficient attention to the selection of the extrusion laminating resin and the extrusion conditions. When sufficient adhesive strength cannot be obtained depending on the combination, or in order to obtain sufficient adhesive strength, the temperature of the resin during extrusion coating is set to a considerably high temperature, the processing speed is limited, etc. Often constrained. .

In the case of a combination in which desired adhesive strength is not obtained, in order to promote adhesiveness with a non-woven fabric, an anchor coating agent is applied to the non-woven fabric in advance, and then a resin is melt-extruded on the adhesive surface with the non-woven fabric. The method is generally done. As the anchor coating agent, an organic titanate-based adhesive, an organic isocyanate-based adhesive, a polyethyleneimine-based adhesive, or the like is used. These adhesives are usually used after being diluted with an organic solvent such as toluene, methanol or hexane.

[0007] However, these methods using the anchor coating agent have a problem that the manufacturing cost is increased by using an expensive anchor coating agent, a problem that a complicated step of applying and drying the anchor coating agent is required, and an anchor coating. The organic solvent that is harmful to the human body scatters during the process of evaporating and drying the organic solvent contained in the agent, and there are many problems such as hygienic problems in the work environment and its surrounding environment and the risk of fire due to the use of flammable organic solvents. Have problems in terms of. further,
In the case of non-woven fabrics having a two-dimensional sheet shape, it is necessary to apply the anchor coating agent several times or more as compared with ordinary plastic substrates having a flat surface shape. Is especially problematic.

[0008]

In view of the above circumstances, the problem to be solved by the present invention is, in the production of a laminate by extrusion coating a resin for extrusion laminating on a non-woven fabric, such as processing temperature and processing speed. Manufactures a laminate that can obtain a strongly bonded laminate without being subject to many restrictions and without using an adhesive such as an anchor coating agent, and can also control the adhesive strength as required. The point lies in providing a method of doing so.

[0009]

In order to solve the above-mentioned problems, the inventors of the present invention have earnestly studied a method for producing a laminate comprising a nonwoven fabric and a resin for extrusion laminating, and as a result,
When extrusion coating a non-woven fabric, it is possible to obtain a strongly bonded laminate by including a specific processing step without using an anchor coating agent, etc., and it is also possible to control the adhesive strength. Heading, completed the present invention.

That is, the present invention is a kind selected from the group consisting of non-woven fabrics, polyethylene resins, polypropylene resins, ethylene-vinyl ester copolymer resins and ethylene- (meth) acrylic acid ester copolymer resins. The present invention provides a method for producing a laminate comprising a resin for extrusion laminating, which comprises the following steps (1) to (3). Steps: (1) A step of subjecting at least one surface of the nonwoven fabric to a surface oxidation treatment. (2) Extruded laminated resin is placed at a resin temperature of 180-
A step of melt-extruding into a film at a temperature of 340 ° C., and subjecting at least one surface of the film to ozone treatment. (3) A step of bringing the surface-oxidized surface of the nonwoven fabric obtained in the step (1) into contact with the ozone-treated surface of the film obtained in the step (2), and press-bonding the film and the nonwoven fabric.

The present invention will be described in detail below. Examples of the nonwoven fabric used in the present invention include nylon-based, polyester-based, polypropylene-based, polyethylene-based, cellulose-based, acrylic-based, polyamide-based, polyurea-based, polyvinyl chloride-based, polyvinyl alcohol-based, polyurethane-based, etc. Using a fiber assembly made of a resin or fibers or a mixture thereof as a raw material, for example, a known method such as a needle punch type, a spun bond type, a stitch bond type, a melt blow type, a spun lace type, a resin bond type or a thermal bond type. Examples of the dry or wet non-woven fabric manufactured by These non-woven fabrics may have a surface previously subjected to a surface treatment such as corona treatment, plasma treatment, flame treatment or the like, or may be pre-printed.

Extrusion laminating resins used in the present invention include polyethylene resins, polypropylene resins,
It is one selected from the group consisting of ethylene-vinyl ester copolymer resins and ethylene- (meth) acrylic acid ester copolymer resins, and these can be used alone or as a mixture of two or more kinds. Further, if necessary, other resins may be mixed in a range of less than 50%.

The method for producing the polyethylene resin is not limited, and it can be produced by, for example, a radical polymerization method or an ionic polymerization method. Examples of the polyethylene-based resin include low-density polyethylene produced by a high-pressure radical polymerization method, high-density polyethylene produced by an ionic polymerization method, and ethylene-α-olefin copolymer obtained by copolymerizing ethylene and α-olefin. Examples thereof include polymers. As the α-olefin, for example, propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, octene-1, decene-1, octadecene-1, etc. α-olefin having 3 to 18 carbon atoms. Examples of the olefin include two or more kinds of these α-olefins.

The method for producing the polypropylene resin is not limited, and it can be produced by, for example, an ionic polymerization method. Examples of the polypropylene resin include a propylene homopolymer, a propylene / ethylene copolymer, a propylene / butene-1 copolymer, and a propylene / α-olefin copolymer. The α-olefin copolymerized with propylene may be used not only in one kind but also in two or more kinds.

The ethylene-vinyl ester copolymer resin and the ethylene- (meth) acrylic ester copolymer resin can be produced by a radical polymerization method, and are obtained by copolymerizing ethylene and a radical-polymerizable comonomer. .

Examples of the vinyl ester of the ethylene-vinyl ester copolymer include vinyl acetate, vinyl propionate and vinyl neoate. Examples of the (meth) acrylic acid ester of the ethylene- (meth) acrylic acid ester copolymer include methyl acrylate,
Ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t acrylate
-Acrylic acid esters such as butyl and isobutyl acrylate, and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate and isobutyl methacrylate And an esterified product of an unsaturated carboxylic acid having 4 to 8 carbon atoms and the like. These comonomers may be used alone or in combination of two or more.

The content of the comonomer component contained in the ethylene-vinyl ester copolymer and the ethylene- (meth) acrylic acid ester copolymer is preferably 30% by weight or less, more preferably 20% by weight or less. .

From the viewpoint of processability, the polyethylene resin, the ethylene-vinyl ester copolymer resin and the ethylene- (meth) acrylic acid ester copolymer resin have a melt flow rate (MF) at 190 ° C.
R) is preferably in the range of 1 to 100 g / 10 minutes, and for polypropylene resins, 230 ° C.
It is preferable that the MFR in is in the range of 1 to 100 g / 10 minutes.

Further, the resin for extrusion lamination used in the present invention is a known additive, for example, an antioxidant, an antiblocking agent, a weathering agent, a neutralizing agent, a flame retardant, within a range that does not impair the effects of the present invention. Antistatic agents, antifogging agents, lubricants, dispersants, pigments, organic or inorganic fillers and the like may be used in combination.

The steps (1) to (3) in the method for producing a laminate of the present invention impart film adhesion to a non-woven fabric without using an anchor coating agent and when laminating at high speed or low temperature. This is a process for doing.

(1) In the step of subjecting at least one surface of the nonwoven fabric to the surface oxidation treatment, the surface oxidation treatment causes oxidation active points at a certain level or higher on the adhesive surface of the nonwoven fabric.
For example, known methods such as corona discharge treatment, plasma treatment, flame plasma treatment, electron beam irradiation treatment, and ultraviolet ray irradiation treatment can be used. However, it is preferable to complete the pressure bonding in step (3) as soon as possible after the surface oxidation treatment, preferably within 1 hour. When the surface oxidation treatment is not performed or after one day or more has passed after the surface oxidation treatment, the effect of improving the adhesive strength may not be obtained, which is not preferable.

The corona discharge treatment is carried out, for example, by using a known corona discharge treatment device and passing the nonwoven fabric through the generated corona atmosphere. Here, from the viewpoint of maintaining the film adhesive strength at a high level, the corona discharge density is
Usually 5 w · min / m ² or more, preferably 25 w · min / m ²
More preferably, it is 40 w · min / m ² or more. The upper limit of the corona discharge density is not particularly limited, but usually ²⁰⁰ w · min / m ² or less is preferable from the viewpoint of economy. At this time, for example, when it is desired to adjust the adhesive strength for adjusting the texture, peeling property, etc., the adhesive strength can be controlled by appropriately adjusting the corona discharge density.

The plasma treatment is carried out by electrically exciting a simple substance or a mixed gas such as argon, helium, krypton, neon, xenon, hydrogen, nitrogen and air with a plasma jet, then removing charged particles, and electrically. It can be carried out by spraying a neutralized excited inert gas onto the surface of the nonwoven fabric.

The flame plasma treatment can be carried out by spraying the ionized plasma in the flame produced when burning natural gas or propane onto the surface of the nonwoven fabric.

The electron beam irradiation treatment is carried out by irradiating the surface of the nonwoven fabric with an electron beam generated by an electron beam accelerator. As the electron beam irradiation device, for example, a device "Electron Curtain" (trade name) that can irradiate a curtain-shaped uniform electron beam from a linear filament can be used.

The ultraviolet irradiation treatment is, for example, 200 to 400.
It can be carried out by irradiating the surface of the nonwoven fabric with ultraviolet rays having a wavelength of mμ.

Further, some commercially available non-woven fabrics have been subjected to surface oxidation treatment such as corona discharge treatment in order to improve the printability on the surface. Such commercial products are subjected to the surface oxidation treatment of the present invention. When used without carrying out
In some cases, the sufficiently strong adhesive strength targeted by the present invention may not be obtained.

(2) 180 to 3 resin for extrusion lamination
In the step of melt-extruding into a film at a temperature of 40 ° C. and subjecting at least one surface of the film to ozone treatment, the ozone treatment may be performed by adding ozone from a nozzle provided in an air gap under the die or a slit-shaped outlet. It is performed by continuously spraying another gas (such as air) on the molten film. At this time, the gas containing the sprayed ozone does not stay in a specific portion,
Further, it is preferable that the molten film is sprayed on the entire surface on the side that comes into contact with the nonwoven fabric. If the ozone nozzle cannot be installed under the die, it may be sprayed on the nonwoven fabric just before pressure-bonding and laminating.

The amount of ozone sprayed depends on the amount of ozone flowing through the molten film.
Normally 1 mg / m2 per unit area ² Or more, preferably
1 to 50 mg / m² , More preferably 1 to 25 mg /
m²Is. When low odor is a problem, it is usually 1
~ 15 mg / m² , Preferably 1 to 13 mg / m² Hope
Good. Adhesion strength to non-woven fabric without ozone treatment
It is not preferable because the effect of improving the degree cannot be sufficiently obtained. Well
In addition, it is not possible to use more ozone treatment than necessary.
It is not preferable because it may worsen the odor of the laminated body.
Yes.

When the resin for extrusion lamination is melt extruded into a film, the resin temperature directly under the die is 180 to 340.
C, preferably 200 to 325 C, more preferably 22.
It is 0-310 degreeC. When low odor is a problem, it is preferably 300 ° C or lower. If the temperature is lower than 180 ° C., the spreadability of the resin will be poor, and it will be difficult to obtain a molten film having a uniform wall thickness, and the adhesive strength with the nonwoven fabric will be insufficient, such being undesirable. On the other hand, if the temperature exceeds 340 ° C., the molten resin is deteriorated and the surface of the molten film is oxidized so much that the odor is deteriorated, which is not preferable.

(3) In the step of bringing the non-woven fabric obtained in the step (1) into contact with the surface treated by oxidation and the ozone-treated surface of the film obtained in the step (2) and press-bonding the non-woven fabric and the film, The process can use known extrusion laminators, including, for example, crimping between chill rolls and nip rolls. In the present invention, it is preferable that the nonwoven fabric after the surface oxidation treatment step of step (1) is immediately subjected to the pressure bonding step of step (3). As a result, a higher level of adhesive strength is developed.

In the present invention, an apparatus in which a non-woven fabric substrate feeding process, a surface oxidation treatment process, a pressure bonding process and a product winding process are sequentially installed on the same line along the flow direction of the non-woven fabric substrate, It is preferable to perform these steps promptly in a series of operations.

Further, in the present invention, from the viewpoint of further improving the adhesive strength, a step of aging the laminate obtained in the pressure-bonding step under heat retention may be provided after the pressure-bonding step. The aging temperature is usually 25 to 70 ° C, preferably 30 to 50 ° C.
More preferably, it is 40 to 45 ° C. The aging time is usually 1 to 120 hours, preferably 10 to 120 hours.
If the aging time is too short, the improvement of the adhesive strength may be insufficient. On the other hand, if the aging time is too long, the coated resin may deteriorate and it is disadvantageous in terms of productivity. To carry out the aging step, a normal oven or a room in which the temperature can be adjusted may be used.

In the present invention, from the viewpoint of further improving the adhesive strength, before the surface treatment step of step (1),
The surface temperature of the non-woven fabric to be subjected to the surface oxidation treatment step is 40
The heating may be performed at a temperature of not less than 0 ° C and not more than 30 ° C lower than the melting point of the non-woven fabric raw material.

The laminate obtained by each of the above-mentioned steps is free from the anchor coating agent component such as the organic solvent remaining,
Not only is there no fear of odor caused by it, but because it can be processed at low temperatures, heat sealability deterioration due to resin deterioration, strength deterioration such as pinhole resistance, deterioration of odor, etc. can be improved, so it is a material for clothing. It can be suitably used as a material for daily life materials, a material for medical hygiene, a material for industrial materials and the like.

[0036]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.
The measurement and evaluation methods performed in Examples and Comparative Examples are as follows. (1) Evaluation of Membrane Adhesion Strength With respect to the adhesive surface of the non-woven fabric of the laminate having a width of 15 mm and the coated resin film, an auto-strain type tensile tester manufactured by Toyo Seiki Co., Ltd. was used, and the adhesion speed was 180 at 200 mm / min. The peel strength at the time of peeling was measured to evaluate the adhesive strength. (2) Odor evaluation 10 cm x 5 cm in an odorless glass 1 liter wide-mouth bottle
Put the laminate cut out in the size of the above, cover with aluminum foil, heat treatment in an oven at 50 ° C for 1 hour, and then 3
Conditioning was performed by gradually cooling for 0 minutes. Thereafter, eight selected panelists sniffed the odor of the laminated body contained in the wide-mouth bottle to determine the odor intensity. The odor intensity at that time was evaluated as 3 ranks, and the rank with the largest number among the 8 panelists was used as the evaluation result of the sample. The symbol of the odor sensory test represents the following judgment. "○": A slight odor is felt. "△": odor is felt. “×”: A strong odor is felt.

Example 1 Spunbond (ELTAS N0504) manufactured by Asahi Kasei Kogyo Co., Ltd. as a non-woven fabric, and low density polyethylene (Sumikasen L716 manufactured by Sumitomo Chemical Co., Ltd.) as a resin for extrusion laminating.
-H; MFR 7 g / 10 min, density 0.919 g / cm ³ ).
And melt-kneading the resin for extrusion laminating with an extruder having a diameter of 65 mm, and the resin temperature directly below the die from the T-die 295
° C, air gap 160mm, film width 380m
m, coating layer thickness 20μ, take-up speed 100 m /
Extruded under the condition of min, and then blown the air containing ozone under the condition that the ozone treatment amount is 12 mg / m ² from the nozzle provided 30 mm below the die on the surface of the molten film that contacts the nonwoven fabric. Then, as a surface oxidation treatment of the non-woven fabric, the corona discharge density of the non-woven fabric surface was 47 w by a corona discharge device provided in-line with the extrusion laminator.
The surface of the non-woven fabric that had been subjected to corona discharge treatment under the condition of min / m ² was extrusion coated, and then pressure-bonded by passing it between a cooling roll and a nip roll at a temperature of 25 ° C. to obtain a laminate. Further, the obtained laminated film was aged in an air atmosphere at 45 ° C. for 48 hours using an oven. Table 1 shows the processing conditions and the evaluation results.

Example 2 The procedure of Example 1 was repeated, except that the corona discharge treatment was carried out under the condition that the corona discharge density on the surface of the nonwoven fabric was 18 w · min / m ² . Table 1 shows the processing conditions and the evaluation results.

Comparative Example 1 Except that neither corona discharge treatment nor ozone treatment was carried out.
The same procedure as in Example 1 was performed. Table 1 shows the processing conditions and evaluation results.
Shown in

Comparative Example 2 The procedure of Example 1 was repeated, except that the corona discharge treatment was not performed and the ozone treatment amount was 24 mg / m ² . Table 1 shows the processing conditions and the evaluation results.

Comparative Example 3 The procedure of Example 1 was repeated, except that the ozone treatment was not performed and the aging treatment was not performed. Table 1 shows the processing conditions and the evaluation results.

Comparative Example 4 The same procedure as in Example 1 was carried out except that the resin temperature immediately below the die of the extrusion laminating resin was 325 ° C., that the ozone treatment was not performed, and that the aging treatment was not performed. Table 1 shows the processing conditions and the evaluation results.

Comparative Example 5 The non-corona discharge treatment was not performed, and an anchor coating agent (Titabond T120, T300 manufactured by Nippon Soda Co., Ltd.) diluted with ethyl acetate to promote adhesion with the non-woven fabric was applied to the non-woven fabric, The procedure of Example 1 was repeated, except that the solvent was evaporated by passing through a drying device at 80 ° C. and then extrusion coating was performed. Table 1 shows the processing conditions and the evaluation results.

[0044]

[Table 1]

[0045]

As described above, according to the present invention, when a resin for extrusion lamination is extrusion coated onto a nonwoven fabric to produce a laminate, an adhesive such as an anchor coating agent is not used, and comparison is made. It was possible to provide a method for producing a laminated body in which a strongly adhered laminated body can be obtained even when processed at extremely low temperature, and the adhesive strength can be controlled if necessary.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D06M 10/00 D06M 10/00 // B29K 23:00 D06M 10/00 H B29L 9:00 (72 ) Inventor Hiroaki Takahata 1-5 Anezaki Kaigan, Ichihara-shi, Chiba Sumitomo Chemical Co., Ltd.

Claims (5)

[Claims] 1. A non-woven fabric and extrusion laminate which is one selected from the group consisting of polyethylene resins, polypropylene resins, ethylene-vinyl ester copolymer resins and ethylene- (meth) acrylic acid ester copolymer resins. A method for manufacturing a laminated body made of a resin, comprising the following steps (1) to (3). Steps: (1) A step of subjecting at least one surface of the nonwoven fabric to a surface oxidation treatment. (2) Extruded laminated resin is placed at a resin temperature of 180-
A step of melt-extruding into a film at a temperature of 340 ° C., and subjecting at least one surface of the film to ozone treatment. (3) A step of bringing the surface-oxidized surface of the nonwoven fabric obtained in step (1) into contact with the ozone-treated surface of the film obtained in step (2), and press-bonding the film and the nonwoven fabric. 2. The production method according to claim 1, further comprising the step of providing the surface oxidation treatment step of step (1) and the crimping step of step (3) in-line, and immediately subjecting the nonwoven fabric after the surface oxidation treatment step to the crimping step. . 3. The production method according to claim 1, wherein the surface oxidation treatment in the step (1) is a corona discharge treatment having a corona discharge density of 5 w · min / m ² or more. 4. The manufacturing method according to claim 1, further comprising the following step (4) after the pressure bonding step of step (3). (4) A step of aging the laminated film obtained in the pressure bonding step under heat retention. 5. The method according to claim 1, wherein the temperature of the resin just below the die when the resin for extrusion lamination is melt extruded into a film is 220 to 310 ° C.