JPS63286342A - Laminate - Google Patents

Abstract

PURPOSE:To improve remarkably the heat resistance of a laminate by a method in which the base film composed of 1.2-polybutadiene having specified vinyl bond content and crystallinity and/or aromatic vinyl compound-conjugated diene block copolymer, is provided with necessary characteristics as the film capable of extending and shrinking, and then polyurethane is laminated on both surfaces or on one surface thereof. CONSTITUTION:Polyurethane layer (layer B) is laminated at least on one surface of the layer (layer A) composed of 1.2 polybutadiene (a-1) having a vinyl content of 70% or more and crystallinity of at least 5% and/or aromatic vinyl compound-conjugated diene block copolymer (a-b). The content of the aromatic vinyl compound is caused to be 10-90 wt.% of total block copolymer (a-2). When a film is formed by mixing (a-1) with (a-2), the mixing ratio of both components is 2-100/98-0. The ratio of the thickness TA of the layer A to the thickness TB of the layer B (TA/TB) is equal to 100/1 or more, when its laminating is carried out on one surface. When the laminating is carried out on both surfaces, (upper and lower layers; TB and intermediate layer; TA) the total TB/TA is equal to 2 or more/100. Total thickness of the laminate is 5-300mum.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a laminate having excellent economy, elasticity, and heat resistance.

b. Conventional technology In the past, in order to improve the adhesion to the thighs when wearing a disposable diaper, for example, a stretched rubber cord, foamed polyurethane, etc. was pasted to the part of the disposable diaper that would come into close contact with the thighs when the diaper was put on, and tension was applied. Taking advantage of the property of rubber strings and the like to recover their elasticity after removing the material, a method was used to provide a part of the cap with elasticity. However, these materials such as rubber string and foamed polyurethane are expensive, which causes an increase in cost. A possible solution to this problem is to make the material thinner, but this is difficult in terms of formability. Therefore, efforts have been made to develop stretchable materials in the form of films or sheets that are inexpensive and easy to handle.

As one such stretchable material, a thermoplastic stretchable material (Japanese Unexamined Patent Publication No. 155478/1983) is known which is made of an aromatic vinyl compound-conjugated diene block copolymer and a butadiene resin and/or a polyolefin resin. ing.

Problems to be Solved by the C0 Invention However, when using such a stretchable material to form, for example, a part of the gears of a disposable diaper as described above, it is necessary to use a true melt adhesive after being slightly stretched. is used to adhere it to the back cover of a disposable diaper, but if the heat resistance of the stretchable material is insufficient, the temperature at the time of adhesion cannot be raised high enough, resulting in poor adhesion. . Also, if the temperature is high enough for bonding,
The elastic material deteriorates due to heat, which can lead to inconveniences such as breakage.

The inventors of the present invention have conducted extensive studies to solve these problems, and have found that 1,2-polybutadiene and/or aromatic vinyl compounds with a vinyl bond content of 70% or more and a crystallinity of 5% or more. We have discovered that a film made of a conjugated diene block copolymer has the necessary properties as a stretchable film, and that by laminating polyurethane on both or one side of the film, the heat resistance can be significantly improved, and we have arrived at the present invention.

A means for solving the d0 problem, that is, the present invention, is: (^) 1.2 polybutadiene (a-1) and/or aromatic vinyl compound having a vinyl bond content of 70% or more and a crystallinity of 5% or more - Conjugated diene block copolymer (a-
The present invention provides a laminate characterized in that (B) a polyurethane layer is laminated on at least one surface of the layer consisting of 2).

(A) 1,2-polybutadiene (a
-1) The 1.2-bond content (vinyl bond content) is 70% or more, preferably 85% or more, and the crystallinity is 5.
% or more, preferably 7 to 60%, more preferably 10
~50%. If the amount of vinyl bond is less than 70% or the degree of crystallinity is less than 5%, moldability and heat resistance will be poor, which is not preferable.

The molecular weight of (a-1) can be selected over a wide range, but in order to fully obtain the effects of the present invention, the intrinsic viscosity (measured in toluene at 30°C) should be 0.5a/- or more, preferably 0.5a/- or more. 7-5a/g, more preferably 1-4a/g
1,2-polybutadiene with a molecular weight corresponding to g is preferred.

Further, the aromatic vinyl compound-conjugated diene block copolymer (a-2) used as a component constituting the layer (A) is
A block copolymer consisting of a vinyl aromatic compound and a conjugated diene, which contains at least one vinyl aromatic compound block and at least one conjugated diene compound block in the molecular chain, and whose molecular chain structure is linear. It may be a chain type or a radial type, or it may be a block copolymer having a so-called tapered block type structure in which a vinyl aromatic compound is gradually increased in a conjugated diene compound block.

For example, as the block copolymer (a-2), (A-B
), , (A-B), -A, (A-B), and X, and the content of the aromatic vinyl compound is preferably 10790 % by weight, more preferably 50% by weight. If the content is less than 10% by weight, the strength of the resulting laminate will decrease, and if it is more than 90% by weight, it will lack flexibility, which is not preferable.

Further, as the vinyl aromatic compound, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, O-methylstyrene, etc. can be used, and among these, styrene is preferred.

Furthermore, as the conjugated diene compound, butadiene,
Examples include isoprene and piperylene, but butadiene and isoprene are preferred.

Furthermore, a hydrogenated version of the block copolymer (a-2) can also be used as a component constituting the layer (A) of the present invention.

(A) consisting of (a-1) and/or (a-2)
The thickness of the layer is preferably 2 to 250 pm, more preferably 5 to 250 pm, particularly preferably 10 to 200 pm.
It is μm. If a film with a thickness of 2 μm or more is used, lamination is difficult, and if a film with a thickness of 250 μm or more is used, it is unfavorable from the viewpoint of economy and flexibility.

Further, when forming a film by mixing (a-1) and (a-2), there is no particular restriction on the mixing ratio of both components, and in either case, both components have sufficient compatibility.

In this case, (a-1) / (a-2) is preferably 2
~100/98-0, more preferably 5-100/9
It is preferable to use a mixture with a mixing ratio of 5 to 0, since a film with even better properties such as permanent elongation, moldability, and texture can be obtained.

(B) Polyurethane, the component constituting the layer, is a polymer having repeating structural units of urethane bonds in its molecules, and is typically produced by polyaddition reactions using diisocyanates, polyols, polyamines, glycols, etc. as raw materials. It is manufactured by a manufacturing method and is used for foams, adhesives, paints, synthetic leathers, and elastomers.

In the present invention, any polyurethane can be used as a component constituting (B), but in particular, the (A) layer and (
B) Thermoplastic polyurethanes are preferred when the layers are laminated by a lamination method, and aqueous polyurethane dispersions are preferred when a coating method is used.

The above-mentioned thermoplastic polyurethane is divided into completely thermoplastic type and incomplete thermoplastic type depending on the synthesis conditions. Whether this type is completely thermoplastic or incompletely thermoplastic is determined by the molar ratio of the OH groups in the difunctional polyol and glycol molecules used as raw materials and the NGO groups in the diisocyanate molecules, and the molar ratio is set to approximately 0. The one synthesized with .95<NGO10H≦1 is completely thermoplastic, and about l<NC010R<
The compound synthesized in 1.1 is an incompletely thermoplastic type. Both types have excellent heat resistance and elasticity, but the incompletely thermoplastic type has particularly excellent heat resistance.

Preferred as the thermoplastic polyurethane is a block copolymer having, for example, a polymer block of bifunctional polyol (polyester or polyether) and diisocyanate as a soft segment and a polymer block of diisocyanate and glycol as a hard segment.

The polyester used as the raw material is poly(1°4-
butylene adipate), poly(l,6-hexane adipate), polycaprolactone, and the like.

In addition, polyethers include polyethylene glycol,
Examples include polypropylene glycol and polyoxytetramethyl glycol.

Furthermore, as glycols, ethylene glycol, 1
．． Examples include 4-butanediol and 1,6-hexanediol.

Diisocyanates include aromatic, alicyclic and aliphatic diisocyanates, such as tolylene diisocyanate,
Examples include 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

The hardness (JIS A) of the thermoplastic polyurethane is preferably 70 to 98, more preferably 70 to 95.

The aqueous polyurethane dispersion used in the coating method is preferably an emulsion in which a polyurethane polymer is dispersed in water, and this dispersion forms a film with excellent heat resistance simply by drying and heat treatment. Further, for example, when a crosslinking agent such as melamine, epoxy, isocyanate, or polyethylene amine, or a catalyst such as amine or amine salt is added to this aqueous dispersion, the heat resistance is further improved.

In addition to polyurethane, other thermoplastic elastomers such as polyolefin elastomers, polyamide elastomers, halogenated polyolefin elastomers, vinyl chloride elastomers, etc. can also be used as the layer (B).

When producing the laminate of the present invention consisting of (A) Ji and (B) layers, it consists of 1,2-polybutadiene and/or aromatic vinyl-conjugated diene block copolymer (^)
The ratio of the thickness TA of the layer to the thickness TI of the layer made of polyurethane is preferably 100/1 or more when the (B) layer is laminated only on one side of the (A) layer, and Preferably it is 10015 to 1/2. When layer (B) is laminated on both sides of layer (A), upper and lower layers: TB, intermediate layer: TB) are preferably the sum of TB/Ta"2 or more/10
0, more preferably 10 or more/100, Tm
/'ra /Tm -1/100 /1~1/1/1
The total thickness of the laminate is preferably 5 to 300 μm from the viewpoint of physical properties and economical efficiency. When layer (B) is laminated only on one side of layer (A), TB/T is within the above range. If Tm/Ta/Ts is out of the above range, heat resistance will be poor, and when the (B) layer is laminated on both sides of the (^) layer, if Tm/Ta/Ts is out of the above range, heat resistance will be poor.

(A) within a range that does not impair the physical properties targeted by the present invention.
The constituent components of the layer and layer (B) include, for example, inorganic fillers such as calcium carbonate, magnesium carbonate, silica, and clay, pigments, lubricants, stabilizers, plasticizers, antiblocking agents, ultraviolet absorbers, and antistatic agents. Further, a crosslinking agent, a catalyst, an antifoaming agent, a thickener, etc. can be added to the (B) layer component.

In addition, by adding a small amount of polyurethane to the 1,2-polybutadiene or aromatic vinyl compound-conjugated diene block copolymer constituting layer (A), layer (A) and (
It is also possible to make the adhesion with layer B even stronger.

1. When using the 2-polybutadiene and aromatic vinyl compound-conjugated diene block copolymer as a component of the (A) layer, a commonly used mixing method may be used, such as a Scrier extruder, Banbury, Methods such as niegoo and roll are used. Further, a mixing method using a tumbler, a Henschel mixer, etc. can also be used for preliminary mixing.

Regarding the lamination method of each layer (A) and (B) of the present invention,
In the lamination method, extrusion lamination,
Hot lamination, dry lamination, etc. are used.
As the coating method, gravure coating, MyArbor coating, doctor blade coating, reverse roll coating, dip coating, air knife coating, calendar coating, squeegee coating, etc. are preferably used.

The laminate of the present invention has excellent permanent elongation (according to the test method shown in the examples), preferably 30% or less, more preferably 20% or less.More preferable physical properties of the laminate of the present invention are The heat resistance using a hot melt adhesive defined in the heat resistance evaluation method of Examples of the present invention is preferably 120°C or higher, more preferably 130°C or higher.

As mentioned above, the laminate of the present invention has excellent permanent elongation properties, excellent elasticity and heat resistance, and is also low-priced and has excellent processability achieved by the manufacturing method. , it is possible to replace conventional rubber cords in other applications. The laminate of the present invention is particularly suitable for applications that do not require much durability, such as disposable products such as disposable diapers and travel pants, and binding tape products.

Furthermore, the laminate of the present invention has excellent heat resistance and elasticity.

Since it has moldability, it can also be used in various fields such as footwear, toys, industrial parts, belts, hoses, medical products, daily necessities, and sheets.

e. Examples Hereinafter, in order to explain the present invention in more detail, the present invention will be explained using examples, but the present invention is not limited to these unless it goes beyond the gist of the present invention.

The characteristics of the laminates obtained in the examples and comparative examples are as follows:
It was evaluated by the following method.

(Evaluation method for processability) The following criteria were used to evaluate the difficulty of film forming using a T-die.

Evaluation criteria: ○: Excellent film formability.

Δ: Slightly poor film formability.

×: Very difficult to form film or impossible.

(Evaluation method for interlayer adhesion) A strip-shaped test piece with a width of 15 m and a length of 100 m was
After 00% stretching, evaluation was made based on the state of peeling between the eyebrows after the stretching force was released.

Judgment criteria: ○: Complete (no peeling.

△D Peeling is observed in some parts.

×: Many parts peeled off or completely peeled off. It's peeling off.

(Evaluation method for heat resistance) A test piece similar to that used for the evaluation of interlayer adhesion was
% stretched, and a melt-based adhesive heated to a constant temperature is dropped onto the layer consisting of component (B) shown in Table 1.

Next, the temperature is increased at 5° C. intervals, and the highest temperature at which the tape is not cut by the true melt adhesive is measured.

(Stretchability evaluation method) A test piece similar to the heat resistance evaluation method was prepared, and 100%
% elongation was applied for 3 minutes, and the length Il) of the test piece was measured 5 minutes after the elongation was released.

Permanent elongation was calculated using the following formula.

Permanent elongation (%)-C1-1! , )/10x100 Here, 10 represents the original length of the test piece, and the smaller the permanent elongation value, the greater the elasticity.

(Text evaluation method) Hand feel of a strip-shaped test piece with a width of 15+a and a length of 15 (texture that cannot be expressed by instrument measurement: important evaluation item)
Evaluate.

Judgment Criteria ○: When the tape is rubbed, it feels elastic and soft without any stiffness.

Δ: When the tape is rubbed, it becomes a little stiff; Slightly lacking in elasticity and slightly soft It doesn't feel good, but it's a problem in practical terms. do not have.

×: When the tape is rubbed, it becomes stiff and elastic. It lacks softness, lacks elasticity, and There is a problem with its suitability as a tape.

Examples 1 to 4.9 to 12 After pre-kneading 1,2-polybutadiene and aromatic vinyl compound-conjugated diene block copolymer at the blending ratios shown in Table 1 and pelletizing them, T was produced using a screw extruder. Using a die, a film with the thickness shown in Table 1 was formed and used as a base film.Next, thermoplastic polyurethane was extruded from the same T-die extruder, and the base film was pressed and laminated with a pressure roll. I got a body. Table 1 shows the evaluation results of the obtained laminated film.

Examples 5 to 6 Table 1 was added to the base film obtained in the same manner as in Example 1.
The emulsions [polyurethane (b) and (c)] shown in were dried at 70°C for 3 minutes and then coated with a doctor blade coater to the coating thickness shown in Table 1 to obtain a laminate. Ta.

Regarding Example 5, it was further dried at 70° C. for 5 hours and used as an evaluation sample. The evaluation results are shown in Table-1.

Example 7 Using a T-die with a screw extruder, the film thickness was approximately 40 mm.
A 1,2-polybutadiene film with a thickness of μm was formed and used as a base film. Next, a laminate was obtained in the same manner as in Example 1. The evaluation results are shown in Table-1.

Example 8 Film thickness of approximately 40μ using a T-die with a screw extruder
m aromatic vinyl compound-conjugated diene block copolymer film (thermoplastic polyurethane-elastolan E18
0 was added to 100 parts of the block copolymer) to form a film to obtain a base film. Next, a laminate was obtained in the same manner as in Example 1. The evaluation results are shown in Table-1.

Comparative Example I A 60 μm film made of 1,2-polybutadiene and a block copolymer composition obtained in the same manner as in Example 1 was used as an evaluation sample. The evaluation results are shown in Table 1. This film has poor heat resistance because it is not laminated with polyurethane.

Comparative Example 2 Using a T-die with a screw extruder, the film thickness was 20μ
A thermoplastic polyurethane film shown in Table 1 of m was obtained. However, since the thermoplastic polyurethane has a high temperature dependence in melt viscosity, it has been extremely difficult to adjust the film thickness. The evaluation results are shown in Table-1.

The results show that a film made only of polyurethane has good heat resistance but is poor in processability.

Comparative Example 3 A laminate was obtained in the same manner as in Example 1 except that a polyester elastomer was laminated instead of the polyurethane layer of Example 1.

As a result, permanent elongation, interlayer adhesion, texture, etc. were inferior. The evaluation results are shown in Table-1.

Comparative Example 4 A laminate was obtained in the same manner as in Example 5, except that a styrene-butadiene copolymer layer was laminated in place of the polyurethane layer in Example 5.

As a result, the obtained laminate had poor heat resistance. The evaluation results are shown in Table-1.

Comparative Example 5 Block copolymer and thermoplastic polyurethane were pre-kneaded and pelletized at the blending ratio shown in Table 1, and then a film with a thickness of about 50 μm was formed using a T-die in a screw extruder. This was used as a sample for evaluation.

The evaluation results are shown in Table-1.

Since this film is a single-layer composition, its heat resistance is somewhat inferior.

Comparative example 6 A laminate shown in Table 1 was obtained in the same manner as in Example 6.

As a result, the obtained laminate had poor heat resistance. The evaluation results are shown in Table-1.

Explanation of notes * in Table 1 (1) 1,2-polybutadiene (a): JSRR
B810 (manufactured by Japan Synthetic Rubber (KK)) Vinyl bond amount: 90%, crystallinity: 18%, [η]
:1.2d! /g (2) 1,2-polybutadiene (b): JSRR
B820 (manufactured by Japan Synthetic Rubber (KK)) Vinyl bond N: 92%, crystallinity: 25%, [η)
: 1, 2 a/g (3) Block copolymer (a): JSRTR20
00 (manufactured by Japan Synthetic Rubber (KK)) (aromatic vinyl content 40% by weight, ABA type) (4) Block copolymer (b): JSRTR
100O (manufactured by Japan Synthetic Rubber (KK)) (aromatic vinyl content 40% by weight, (A-8), X type) (5) Block copolymer (c): Asabrene T431
(Manufactured by Asahi Kasei Kogyo (KK)) (Aromatic vinyl content: 27
Weight %, (A-B), X type) (6) Polyurethane (A): Adibate ester thermoplastic polyurethane, Elastolan f! 18G (manufactured by Nippon Elastolan (KK)) (Hardness (JIS-A); 8
0) (7) Polyurethane (b): Polyurethane high polymer aqueous emulsion, Rezamin-7510 (manufactured by Dainichiseika Kogyo (KW)) (hardness (JIS-A); 95) 4 parts), crosslinker Rezamin UM-50 (5 parts) and aqueous ammonia 25% (0.5 parts)
The amount in parentheses is the amount added to 100 parts of emulsion polymer net.

(8) Polyurethane (c): Elastolan E180
Water-based emulsion (prototype made by emulsifying with Japan Synthetic Rubber (K) using the above Elastlan E180) (9) Polyester elastomer (d): Perbrene P150M (manufactured by Toyobo (KK)) α Styrene-butadiene copolymer latex (e)
: JSR2108 (manufactured by Japan Synthetic Rubber (KK)) 10 As described in detail of the invention, according to the present invention, 1,2-polybutadiene and/or aromatic vinyl having a specific vinyl bond amount and crystallinity The base film made of a compound-conjugated diene block copolymer has the necessary properties of elasticity and film, and by laminating polyurethane on both sides or one side, the heat resistance is greatly improved. It is possible to obtain a laminate that is economically efficient and has an excellent balance of properties such as heat resistance, elasticity, moldability, and texture.

Patent applicant: Japan Synthetic Rubber Co., Ltd. (2 others)

Claims (4)

[Claims] (1) (A) 1,2 polybutadiene (a-1) and/or aromatic vinyl compound-conjugated diene block copolymer (a-2) having a vinyl bond content of 70% or more and a crystallinity of 5% or more A laminate characterized in that (B) a polyurethane layer is laminated on at least one surface of the layer consisting of (B). (2) The composition of the (A) layer is (a-1)/(a-2) = 2~
100/98~0, The laminate according to claim (1). (3) Ratio of thickness of layer (B) and layer (A) (T_B/T_A
), but when layer (B) is laminated on one side of layer (A), T_
When the ratio of B/T_A is 1 or more/100, and the (B) layer is laminated on both sides of the (A) layer, the total thickness of the T_B layer/T_A=
2 or more/100, and the total thickness of the laminate is 5 to 300
The laminate according to claim (1), which has a diameter of μm. (4) Aromatic vinyl compound-conjugated diene block copolymer (a-2) is a block copolymer consisting of a vinyl aromatic compound and a conjugated diene, and has at least one vinyl aromatic compound in the molecular chain. A block copolymer (a-2) containing a compound block and at least one conjugated diene compound block, the aromatic vinyl compound content of which is all block copolymer (a-2)
The laminate according to claim 1, wherein the content is 10 to 90% by weight.