JPH1148410A - Expandable and contractible film laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expandable and contractible film laminate to be incinerated without generating harmful substance and efficiently regenerated with recyclability, by incorporating satisfactory drape and high peel strength. SOLUTION: An expandable and contractible film laminate is manufactured by thermally bonding an expandable and contractible film containing thermoplastic elastomer composition containing (d) 2 to 40 pts.wt. of inorganic filler to total sum of 100 pts.wt. of (a) 30 to 80 wt.% of ethylene elastomer containing 4-8C α-olefin comonomer and having a density of 0.86 to 0.90 g/cm<3> , melt index (190 deg.C, 2.16 kg of load) and weight-average molecular weight/number-average molecular weight of 1.8 to 2.8, (b) 10 to 60 wt.% of thermoplastic elastomer and (c) 5 to 20 wt.% of polyethylene having a density of 0.915 to 0.950 g/cm<3> to woven fabric or nonwoven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretchable film laminate, and more particularly to a stretchable film laminate suitable for disposable gloves, disposable wear, disposable diapers, napkins and other stretchable members, and stretchable compresses.

[0002]

2. Description of the Related Art Gather members, such as disposable diapers for baby and adults, and napkins with gathers, are required to have elasticity. As such a stretchable member, a stretchable film such as a polyurethane foam, a polyurethane film or a natural rubber film and a nonwoven fabric or the like are joined by a hot melt adhesive or heat-sealed by heat sealing.

[0003] However, polyurethane foams have problems such as low strength and high price, and polyurethane films have too high stretching strength, poor hot melt adhesion, easy blocking, and difficulty in film formation. There are problems such as the necessity of using release paper. Although natural rubber films have an advantage in price, they have problems in hot melt adhesiveness, thermal adhesiveness and the like. Further, disadvantages common to these stretchable films are that they cannot be recycled or cannot be incinerated due to generation of harmful substances.

In addition, since the stretchable film is flexible, has a low tensile strength, and has poor thermal adhesiveness to a nonwoven fabric or the like, when hot pressing is performed, the bonding speed must be reduced and the pressing force must be increased. No. For this reason, the laminate of the stretch film and the nonwoven fabric obtained by hot pressing has a hard and stiff feel.

Further, since the adhesive strength between the stretchable film and the nonwoven fabric is weak, peeling occurs only by hand-rubbing in water,
Since the stretchable film becomes brittle after a long heating time, even if it is rubbed lightly, the material is destroyed.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a good texture and a high peel strength,
An object of the present invention is to provide a stretchable film laminate that can be recycled, can be incinerated without generating harmful substances, and can be thermally bonded efficiently.

[0007]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned object, the present inventors have found that as a stretch film which is hot-pressed with a woven or non-woven fabric, an ethylene-based elastomer and a heat-resistant film having a different solubility parameter from the elastomer. When a stretchable film containing a plastic elastomer is used, the obtained stretchable film laminate not only has a good texture and high peel strength, but also can be recycled and incinerated because of good thermal adhesion. Discovered and completed the present invention.

That is, the stretchable film laminate of the present invention comprises (a) 18 to 40% by weight of an α-olefin comonomer having 4 to 8 carbon atoms, a density of 0.86 to 0.90 g / cm ³ ,
~ 50g / 10min melt index (190 ° C, load 2.16
kg) and 30 to 80% by weight of an ethylene elastomer having a weight average molecular weight / number average molecular weight of 1.8 to 2.8, (b) 10 to 60% by weight of a thermoplastic elastomer, and (c) a density of 0.915.
0.95 g / cm ³ of polyethylene and 5 to 20% by weight in total of 10
0 parts by weight, (d) a stretchable film made of a thermoplastic elastomer composition containing 2 to 40 parts by weight of an inorganic filler, and a stretchable woven or nonwoven fabric, which are thermally bonded. And

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. [A] Configuration of stretch film laminate [1] Stretch film (A) Composition (1) Essential component (a) Ethylene elastomer Ethylene elastomer has a density of 0.86 to 0.90 g / cm ³ ,
Melt index (MI: 190 ° C, load 2.16kg) is 0.
1 to 50 g / 10 min, weight average molecular weight / number average molecular weight of 1.8
2.8, preferably 18 to 40% by weight of an α-olefin comonomer having 4 to 8 carbon atoms.

If the MI is less than 0.1 g / 10 minutes, the torque increases during the film formation and extreme melt fracture occurs. If the MI exceeds 50 g / 10 minutes, the bubbles of the blown film become unstable and the film formation becomes unstable. Is reduced. A more preferred MI is 0.5 to 20 g / 10 minutes.

As the α-olefin comonomer, 1-
Butene, 1-pentene, 1-hexene, 4-methyl-1
-Pentene, 1-heptene, 1-octene and the like can be mentioned, among which 1-octene is preferable. When the content of the α-olefin comonomer is less than 18% by weight, sufficient flexibility cannot be obtained, and when it exceeds 40% by weight, the elastomeric property is rather deteriorated. A more preferred content of the α-olefin comonomer is 20 to 35% by weight, particularly 22 to 30% by weight.
It is.

As described above, in order to produce an ethylene elastomer having a narrow weight average molecular weight / number average molecular weight (Mw / Mn) of 1.8 to 2.8, which is a measure of the molecular weight distribution, ethylene and an α-olefin are used in the presence of a metallocene catalyst. The comonomer is solution polymerized. Metallocene catalysts are titanium, zirconium, metallocene having a structure in which a transition metal such as hafnium is sandwiched by an unsaturated cyclic compound containing a π-electron cyclopentadienyl group or a substituted cyclopentadienyl group, and an aluminum compound. It is a combination with a co-catalyst. Examples of the metallocene include titanocene and zirconocene, and examples of the cocatalyst aluminum compound include alkylaluminoxane, alkylaluminum, aluminum halide, and alkylaluminum halide.

[0013] Commercially available ethylene elastomers include Exact (exxon chemical) and Tuffmer (mitsui petrochemical).

(B) Thermoplastic Elastomer The thermoplastic elastomer is a polyolefin and includes, for example, an ethylene-methyl methacrylate copolymer and an ethylene-methyl acrylate copolymer. Is preferred.

The ethylene-methyl acrylate copolymer has a methyl acrylate content of 5 to 40% by weight,
Melt flow rate (MFR: 190 ° C, load 2.16kg)
0.2 to 50 g / 10 min, preferably 2 to 25 g / 10 min.

It is necessary that the solubility parameter (SP value) of the thermoplastic elastomer is 8.0 to 11.0 and is larger than the solubility parameter (SP value) of the ethylene elastomer. Here, the solubility parameter (SP value) is
SP = dΣG / M (where M is the molecular weight of the structural unit of the polymer, d is the density of the structural unit, and G is a constant specific to the structural unit).

(C) Polyethylene Polyethylene has a density of 0.915 to 0.950 g / cm ³ and a melt index of 0.5 to 10 g / 10 min (MI: 190
And a load of 2.16 kg). As such polyethylene, low-density polyethylene obtained by a high-pressure method having a density of 0.925 g / cm ³ or less, obtained by copolymerizing with a trace amount of an α-olefin such as 1-butene in the presence of a Ziegler catalyst. Linear low density polyethylene (LLDPE) with a density of 0.920 to 0.930 g / cm ³ and a density of 0.92
6 to 0.940 including but density polyethylene in a g / cm ^3,
Among them, high-pressure low-density polyethylene is preferable.

(D) Inorganic filler Examples of the inorganic filler include talc, calcium carbonate, zeolite, gypsum, carbon black, mica, clay, kaolin, silica, and diatomaceous earth. Of these, talc and calcium carbonate are preferable. . These inorganic fillers have an average particle diameter of 0.5 to 5 μm and are preferably treated with a surface treating agent such as a fatty acid.

(2) Other components In addition to the above essential components, an antioxidant,
Other components such as an ultraviolet absorber and a colorant can be appropriately compounded.

(3) Compounding amount The composition of the stretchable film is as follows:
30 to 80% by weight, and (b) the thermoplastic elastomer is 10 to
60% by weight, (c) 5 to 20% by weight of polyethylene, and (d) 2 parts by weight of inorganic filler per 100 parts by weight of resin component.
~ 40 parts by weight. Also preferably, (a) is 30 to 50% by weight, (b) is 30 to 50% by weight, (c) is 5 to 15% by weight, and (d) is 100% by weight of the resin component. 5-15 for
Parts by weight.

When the content of the ethylene-based elastomer is less than 30% by weight, the flexibility of the stretchable film is insufficient, and when it exceeds 80% by weight, the opening property and the film formation stability at the time of film formation by the inflation method are deteriorated. 10% by weight of thermoplastic elastomer
When the amount is less than the above, melt fracture occurs due to a large torque at the time of film formation. When the amount exceeds 60% by weight, pinholes and the like are generated during the film formation, and it becomes difficult to form the film. If the polyethylene content is less than 5% by weight, the stability of bubbles at the time of film formation by the inflation method deteriorates, and if it exceeds 20% by weight, the strain when the film is stretched (for example, at 100% stretching) increases. Furthermore, when the amount of the inorganic filler is less than 2 parts by weight,
The opening properties and blocking resistance of the blown film are deteriorated, and if it exceeds 40 parts by weight, the flexibility is insufficient.

(B) Structure The thickness of the stretch film is preferably 150 μm or less, more preferably 20 to 60 μm. If the thickness exceeds 150 μm, the stretch film becomes hard and the texture deteriorates. The stretch ratio of the stretchable film is the draft ratio in the longitudinal direction ((die lip gap) / (film thickness))
The blow-up ratio in the lateral direction ((diameter of bubble) / (diameter of die)) is preferably at least two times.

(C) Production Method The stretchable film is prepared by dry blending the above components (a) to (d) and optional components using, for example, a Henschel mixer, a high-speed mixer or the like, and using an extruder or the like for about 150 to 190. It is obtained by melt-kneading at ° C., pelletizing, and then forming a film by an inflation method or the like.

As a film forming method, a T-die / tenter method can be used, but an air-cooled inflation method for efficiently forming a biaxially stretched film is preferable. As the conditions of the air-cooled inflation method, it is preferable to extrude at a temperature of about 150 to 180 ° C. and to biaxially stretch the obtained annular resin film at a blow ratio of 2.0 to 5.0. An elastic film produced by an air-cooled inflation method or the like is slit into a predetermined width.

[2] Woven Fabric or Nonwoven Fabric The woven fabric or nonwoven fabric to be laminated with the stretchable film may be formed of any of natural fibers and synthetic fibers as long as it has at least the property of elongation. Cloths or nonwovens are preferred. Raw materials for synthetic fibers include polyester acetate, polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), nylon, acrylic resin, polypropylene, polyethylene,
Examples include polyphenylene sulfide and polyurethane. Among them, a spunlace nonwoven fabric of polyester or polypropylene is preferable.

Examples of the woven fabric include stretch woven fabric, knitted fabric, knitted fabric and the like. In addition, as a nonwoven fabric,
A web formed of a web of natural fibers or synthetic fibers by a wet method or a dry method may be used. Examples of the web forming method include a melt spinning method such as air jet drawing (spun bond method), spunlace method, roll drawing, melt blow method, flash spinning method, and wet spinning method. In particular, it is preferable to entangle the fibers by applying a water jet to the web.

It is necessary that the woven or nonwoven fabric does not substantially melt or shrink during the hot pressing process.
Therefore, the melting point or secondary transition point of the woven or non-woven fabric needs to be at least 20 ° C. higher than that of the stretchable film.
The basis weight of the woven or nonwoven fabric is preferably ^{15~100 g / m 2, 20~60g /} m 2 is more preferable.

[B] Method for Producing Stretched Film Laminate [1] Thermal Bonding The heat bonding between the stretchable film and the woven or nonwoven fabric is preferably performed by hot pressing. A hot roll is used for hot pressing, at a temperature of 40 to 180 ° C. and a pressure of 0.5 to 5 kgf / cm ² .

When hot pressing is performed by a heat roll,
In addition to pressing the stretchable film and the woven or nonwoven fabric one by one, the structure is such that the woven or nonwoven fabric is sandwiched between two stretchable films, or conversely, the stretchable film is sandwiched between two woven or nonwoven fabrics. Or you may.

[2] Improvement of thermocompression bonding Since the stretch film used in the present invention has high thermal adhesiveness, the laminating speed should be 20 to 40 m / min under the conditions of 180 ° C. and 2 kgf / cm ² , for example. Can be. Since the time for receiving the heat history during the hot pressing step is short, the laminated body can be thermally bonded without impairing the feeling. Even when the stretch film and the woven or nonwoven fabric are spot-bonded using the embossing roll, a stretch film laminate having a sufficient peel strength can be obtained.

[0031]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Embodiment 1 1. Production of stretchable film (1) Material (a) Ethylene-based elastomer: Ethylene-based elastomer produced by using a metallocene catalyst (manufactured by Dow Chemical Company, trade name Engage EG8150; MI 0.5 g / 10 min, density
0.868 g / cm ³ , Mw / Mn = 2.0, 1-octene content
28% by weight). (b) Thermoplastic elastomer: ethylene-methyl acrylate copolymer (manufactured by Exxon Chemical Co., Ltd., trade name Optima TC-130; MFR 20 g / 10 min, density 0.940 g / cm ³ , methyl acrylate content 21% by weight). (c) Polyethylene: high-pressure low-density polyethylene (manufactured by Nippon Unicar Co., Ltd., trade name NUC-8506; MI 0.8 g / 10 min,
Density 0.923 g / cm ³ ). (d) Inorganic filler: calcium carbonate (manufactured by Shiraishi Calcium Co., Ltd., trade name: PO Filler 150B; average particle size 1.5 μm,
Bulk density 0.4 g / cm ³ ).

(2) Production method (a) 41 parts by weight of component, 41 parts by weight of component (b), 9 parts by weight of component (c) and 9 parts by weight of component (d) were mixed with a super floater (manufactured by Kawata Corporation, model After dry-blending using SFC-50), the mixture was melt-kneaded at 170 ° C. using a twin-screw extruder (Model TEX-30, manufactured by Nippon Steel Works, Ltd.).

Using the obtained resin composition, a film having a thickness of 30 μm and a folding width of 600 mm is manufactured by an air-cooled inflation film forming apparatus under the condition of a blow-up ratio of 3.8, and the tube is wound into a length of 30 m in a tube shape. did. The bubbles during inflation film formation were stable. The obtained stretch film
The test piece was cut into a size of 15 mm × 150 mm.

2. Preparation of nonwoven fabric The nonwoven fabric used is the following commercially available product. 15mm each nonwoven
A test piece was cut into a size of × 150 mm. (a) Polypropylene (PP) non-woven fabric (off-the-shelf): thickness 15
0 μm, basis weight 30 g / m ² . (b) Polyethylene (PE) non-woven fabric (off-the-shelf): thickness 150
μm, basis weight 30 g / m ² . (c) Polyethylene terephthalate (PET) non-woven fabric (off-the-shelf product): 150 μm in thickness, 30 g / m ^{2 in} basis weight.

3. Hot compression bonding The above elastic film and non-woven fabric test pieces are stacked one by one,
Using a heat sealer (manufactured by Fuji Impulse Co., Ltd., policyr 210E) at 120 ° C. and 2 kgf / cm ²
The laminate was obtained by heating and pressing for 2 seconds. The heat seal length was 15 mm, and the heat seal width was 1.0 mm.

4. Measurement and evaluation of physical properties Measurement and evaluation of physical properties of each laminate were performed by the following methods. Table 1 shows the results. (1) Heat seal strength (gf / 15mm) Measured with the following equipment and conditions in accordance with JIS L1096. Equipment used: Strograph W (manufactured by Toyo Seiki Co., Ltd.) Chuck interval: 50 mm Peeling speed: 300 mm / min Measurement atmosphere: 23 ° C, 50% RH

(2) Peel strength Each laminate was immersed in water at 30 ° C. for 2 hours, and then hand-rubbed while immersed, and the peel strength was evaluated according to the following criteria.・ ・ ・: No peeling. Δ: Peeled off by hand massage.・ ・ ・: Peeled before hand massage. ×: Unevaluable (no adhesion).

(3) Feeling Touch was evaluated according to the following criteria.・ ・ ・: Soft and good feel. Δ: Roughness and poor feel. ×: Unevaluable (no adhesion).

Comparative Example 1 A polyurethane foam (commercial product) having a thickness of 1.5 mm was used as a stretch film, and heated at 160 ° C. and 2 ° C. with a heat sealer (manufactured by Fuji Impulse Co., Ltd., type Policyler 210E).
A laminate was manufactured in the same manner as in Example 1 except that heating and pressure bonding were performed for 1 ^{second under} the condition of kgf / cm ² , and physical properties were measured and evaluated. The results are shown in Table 1 below.

Comparative Example 2 A polyurethane film having a thickness of 30 μm (manufactured by Tonen Chemical Co., Ltd.) was used as a stretchable film, and was heated with a heat sealer (manufactured by Fuji Impulse Co., Ltd., policyler 210E type).
A laminate was produced in the same manner as in Example 1 except that the laminate was heated and pressed at 1 ° C. and 2 kgf / cm ² for 1 second, and physical properties were measured and evaluated. The results are shown in Table 1 below.

Comparative Example 3 Using a natural rubber film (commercially available) having a thickness of 0.2 mm as a stretch film, a heat sealer (Fuji Impulse Co., Ltd.)
160 ° C and 2kgf / cm
^A laminate was produced in the same manner as in Example 1 except that heating and pressure bonding were performed under ^two conditions for 1 second, and physical properties were measured and evaluated. The results are shown in Table 1 below.

Table 1 Heat seal Peeling strength Touch example No. Film nonwoven fabric strength ⁽¹⁾ Degree evaluation Evaluation Example 1 Stretchable film PP nonwoven fabric 330 ○ ○ PE nonwoven fabric 430 ○ ○ PET nonwoven fabric 300 ○ ○ Comparative example 1 Polyurethane PP nonwoven fabric 30 ▲ △ Foam PE non-woven fabric 50 ▲ △ PET non-woven fabric 10 ▲ △ Comparative example 2 Polyurethane PP non-woven fabric 0 × × Film PE non-woven fabric 0 × × Comparative example 3 Natural rubber PP non-woven fabric 0 × × Film PE non-woven fabric 0 × × PET non-woven fabric 0 × × Note: (1) Unit: gf / 15mm.

As is evident from Table 1, the laminate of Example 1 in which the stretchable films were thermally bonded has good heat seal strength and peel strength, and also has an excellent texture.

[0045]

As described in detail above, since the stretchable film laminate of the present invention is formed by laminating stretchable films having excellent thermal adhesiveness, the heat history at the time of thermal bonding with a nonwoven fabric or the like is reduced. High peel strength and good texture. Since the stretchable film laminate of the present invention can be recycled and incinerated without generating harmful substances, it is suitable for stretchable members such as disposable gloves, disposable wear, disposable diapers and napkins, stretchable compresses and the like.

Claims (5)

[Claims] (1) A melt index (190) containing from 18 to 40% by weight of an α-olefin comonomer having 4 to 8 carbon atoms, having a density of 0.86 to 0.90 g / cm ^{3 and} a content of 0.1 to 50 g / 10 min.
C., load 2.16 kg) and 30 to 80% by weight of an ethylene-based elastomer having a weight average molecular weight / number average molecular weight of 1.8 to 2.8; (b) 10 to 60% by weight of a thermoplastic elastomer;
(D) Stretchable film comprising a thermoplastic elastomer composition containing 2 to 40 parts by weight of an inorganic filler with respect to 100 parts by weight in total of 5 to 20% by weight of polyethylene having a density of 0.915 to 0.950 g / cm ³ And a woven or non-woven fabric. 2. The stretchable film laminate according to claim 1, wherein the ethylene-based elastomer is copolymerized in the presence of a metallocene catalyst. 3. The stretchable film laminate according to claim 1, wherein the thermoplastic elastomer is a polyolefin-based elastomer. 4. The stretchable film laminate according to claim 1, wherein the thermoplastic elastomer has a solubility parameter of 8.0 to 11.0 and is greater than the solubility parameter of the ethylene-based elastomer. Stretchable film laminate. 5. The stretchable film laminate according to claim 1, wherein the stretchable film and the woven or nonwoven fabric are hot-pressed at 70 to 140 ° C. and 0.1 to 10 kgf / cm ^2. A stretchable film laminate characterized in that: