JPH05301288A - Moisture shrinkable split cloth - Google Patents

Abstract

PURPOSE:To obtain split cloth which is capable of making compact packing and superior in permeability to air and permeability to water also after the packing, by a method wherein the split cloth is formed of a stretched molded matter which shrinks at a specific ratio by moisture or water. CONSTITUTION:A matter which shrinks by at least 10% by moisture or water is used as a stretched molded matter. A graft and/or block copolymer of hydrophilic resin and thermoplastic resin, a mixture of the hydrophilic resin and thermoplastic resin and a hydrolyzed matter of a vinyl ester homopolymer or a copolymer can be mentioned as this material. Especially the strectched molded matter from a partial hydrolyzed matter (hydrolysis rate is 0.1-75mol%) of the vinyl ester homopolymer is preferable. A manufacture of split cloth can be made easily by, for example, a split.process method. This moisture shrinkable split cloth is especially suitable as a bag for waste matters having favorable water draining-off, a sand bag material and a tea bag material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split cloth having a property of shrinking due to moisture or water.

[0002]

2. Description of the Related Art Conventionally, split cloth is widely used as a material having good air permeability and water permeability in various applications such as packaging in a sheet shape or a bag shape. Heat shrinkable films (for example, polyvinyl chloride film, polyethylene film, polypropylene film, etc.) are known as materials for compactly packaging materials.

[0003]

However, since all the conventional split cloths have a constant size, there is a problem in that, for example, when they are used for packaging, if the content is small, they are bulky. On the other hand, the heat-shrinkable film generally has poor air permeability and water permeability, and has a problem in handling such as requiring a special heating device when shrinking.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that if a split cloth made of a stretched molded article having a property of easily shrinking at a temperature near room temperature is used. The inventors have found that the above problems can be easily solved, and have reached the present invention. That is, the present invention is a split cloth made of a stretch-molded product having a property of shrinking at least 10% by moisture or water.

In the present invention, examples of the stretch-molded article include those selected from the following (1) to (4). (1) Stretched and molded product from graft and / or block copolymer of hydrophilic resin and thermoplastic resin; stretched film from graft copolymer of starch derivative and polymethyl acrylate (US Pat. No. 4,839,450, etc.), Stretched film from a graft copolymer of a cellulosic polysaccharide and a thermoplastic resin (Japanese Patent Laid-Open No. 03-177431, etc.), stretched film from a graft copolymer of a hydrophilic synthetic resin and a thermoplastic resin (Japanese Patent Laid-Open No. 03-177431) -37233, etc.), a stretched film made of a block copolymer of a hydrophilic synthetic resin and a thermoplastic resin (Japanese Patent Laid-Open No. 03-39331, etc.), and the like. (2) Stretch-molded products from a mixture of hydrophilic synthetic resin and thermoplastic resin; JP-A-03-37232 and the like. (3) Stretched molded product from hydrolyzate of vinyl ester (co) polymer; stretched film from polyvinyl alcohol having a saponification degree of 98 mol% or more (JP-A-57-160615, etc.),
Stretched film from vinyl ester homopolymer [Partially hydrolyzed polyvinyl acetate (hydrolysis rate 0.1-75 mol%)
Etc.], a stretched film from a vinyl ester copolymer [a stretched film from a partially hydrolyzed product of a copolymer of vinyl acetate and vinyl formate (hydrolysis rate 0.1 to 75 mol%)] and the like. (4) Vinyl ester and / or alkyl (meth)
Stretched and molded product comprising a random copolymer containing acrylate as a constituent unit; for example, vinyl ester compound and / or
Or a stretched film or the like from a random copolymer composed of a polymerizable monomer (X1) unit selected from alkyl (meth) acrylate and a polymerizable monomer (X2) unit selected from the following a to f .. a. Vinyl carboxylic acid, its anhydride or its monovalent salt b. Vinyl sulfonic acid, or its monovalent salt c. Hydroxyalkyl (meth) acrylate d. Allyl alcohol e. Polyhydric alcohol monoallyl ether f. Polyoxyethylene Mono (meth) acrylate

Among the above, the preferred one is (3),
Particularly preferred is a stretched molded product from a partially hydrolyzed product of a vinyl ester homopolymer (hydrolysis rate: 0.1 to 75 mol%).

Further, these stretch-molded products may be appropriately crosslinked so long as the shrinkability is not impaired.

In the stretched molded product, if necessary, as a filler and an additive, a plasticizer, a foaming agent, a lubricant, a surfactant, a readily decomposable additive, an antistatic agent, a colorant, a filler, an inorganic substance (silica, Zeolite, activated carbon, far infrared radiation ceramics, etc.), water absorbent resin, deodorant, fragrance, medicinal component,
It may contain antibacterial agents, antifungal agents and the like.

The stretch-molded product may be uniaxially stretched or biaxially stretched. The stretch ratio varies depending on the purpose of use and the manufacturing method, but in the case of the blown film of (3), the stretch ratio is usually 2 to 50 in both the MD and TD directions. The thickness of the film is not particularly limited, but usually 10 to 100 μm is preferable.

There is no particular limitation on the method for producing the split cloth of the present invention by molding the stretch-formed product, but the shrinkable split cloth of the present invention can be easily prepared by a known method such as a split process method. You can do it.

In the moisture-shrinkable split cloth of the present invention, the cross-linked fiber nets may be bonded at the intersections or may be left unbonded. Adhesion is preferable when strength is required.

The stretched film used for the moisture-shrinkable split cloth of the present invention is usually immersed in water or at a relative humidity of 70%.
It can be easily contracted by exposing it to a condition of more than%. The degree of contraction depends on the purpose of use,
Usually, it is at least 10% in the temperature range of 0 to 50 ° C under the above-mentioned humidity conditions.

The moisture-shrinkable split cloth of the present invention is usually composed of the stretched film alone, but may be composed of other materials such as a plastic film if necessary. For example, (a) by coextrusion molding, heat sealing, adhesion, etc., the stretched film and other plastic films are laminated to form a multilayer structure, (b) the stretched film is laminated on other non-woven fabric, paper, etc. Etc.

As a method of shrinking the moisture-shrinkable split cloth of the present invention when it is actually used, for example, a method of putting an article to be packaged containing moisture into the split cloth formed in a bag shape,
Put the object to be packed in the split cloth formed in a bag in advance,
Examples thereof include a method of putting in water, a method of previously putting an article to be packaged in the split cloth formed in a bag shape, and applying moisture by spraying. Of these, the method of or is preferred.

The moisture-shrinkable split cloth of the present invention shrinks when it comes into contact with moisture or water by the above-mentioned method and contracts to adhere to the article to be packaged, so that compact packaging is possible,
Moreover, the water may be drained due to the contraction pressure. Further, it is possible to secure air permeability and water permeability after shrinkage. In addition, since it becomes soft when it comes into contact with water, it is easy to attach and detach.

Since the moisture-shrinkable split cloth of the present invention can shrink and closely pack even an object having a complicated shape, it can be manufactured in a simple shape and the manufacturing cost, distribution cost and the like can be reduced.

Since the moisture-shrinkable split cloth of the present invention does not shrink unless it is re-stretched after shrinking, it is usually used for disposable applications.

[0018]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. The shrinkage ratios in the examples are the vertical line (longitudinal direction of the bag-like object) and the horizontal line (longitudinal direction of the bag-like object) drawn in the central part of the split cloth after leaving each sample for 1 minute under various conditions. (Perpendicular to the vertical direction) was calculated from the ratio of the length before moisture absorption and the length after moisture absorption. Further, in the case of the blown film, the draw ratio was calculated from the ratio of the take-up speed during film formation and the extrusion speed from the die. In the case of stretching by the roll heating method, it was calculated from the ratio of length before and after stretching.

Example 1 (Distribution of a film of a partial hydrolyzate of vinyl ester) An inflation film of a partial hydrolyzate of polyvinyl acetate (polymerization degree: 1,500) (hydrolysis rate: 3 mol%) [stretching ratio; MD 40 times in the direction, 3 times in the TD direction, thickness (20 μ)] was formed into a wide split fiber network, assembled in the length and width directions, and the crossing portions were bonded by heat sealing to obtain a moisture shrinkable split cloth of the present invention. This split cloth is vertical
After molding into a bag of 50 cm × 30 cm in width, when household garbage containing water was put in, it quickly shrank, and a compact garbage-processed product with no water was obtained. By putting this treated product in a conventional household garbage bag and discarding it, it was possible to easily and hygienically treat the garbage containing a large amount of water. The shrinkage factor of the split cloth at this time was 20% in both the longitudinal direction and the lateral direction.

Example 2 The bag-shaped split cloth prepared in Example 1 was filled with 70% by volume of sand, and the bag mouth was tied with a string. After placing this sandbag as a sandbag in a complicated shape to adjust the shape and then watering it, the excess bag portion quickly contracted, and a sandbag conforming to the shape of the installation location was easily obtained. ..

Example 3 (Split cloth composed of a film of a mixture of a hydrophilic resin and a thermoplastic resin) Methyl acrylate was polymerized by a known method in an aqueous solution of polyvinyl alcohol (polymerization degree: 1750, saponification degree: 98.5%). A mixture of polyvinyl alcohol and polymethyl acrylate was obtained. After this mixture was dried and pulverized, it was dissolved in dimethyl sulfoxide and a uniform film was obtained by the casting method. This film was uniaxially stretched with a roll heating type stretching machine to obtain a film with a thickness of 20 μ (stretching ratio length 3 times).
Using this film, a split cloth of the present invention was obtained in the same manner as in Example 1 except that the intersections of the wide split fiber networks were not bonded. When this split cloth was molded into a tea bag and tea was put into it, the tea bag was 40
Even in hot water at about ℃, it contracted rapidly, the active ingredient was squeezed out well, and the drainage after taking out from the hot water was extremely good as compared with the conventional one. The shrinkage ratio of the split cloth at this time was 18% in the longitudinal direction and 18% in the lateral direction.

[0022]

The moisture-shrinkable split cloth of the present invention has the following effects. (1) Since it shrinks rapidly in response to moisture or water and adheres to the specific package, it is possible to perform compact packaging at room temperature as compared with the conventional split cloth. (2) Due to the mesh structure, it has excellent breathability and water permeability. (3) Since the object to be packaged is pressed by the contraction pressure at the time of contraction, when the object containing a large amount of water is packaged, the water drainage is extremely good. (4) By shrinking, it fits perfectly into a complicated object to be packaged. Therefore, at the time of manufacturing, the shape may be simple, and the manufacturing process can be simplified. (5) Further, since it has a simple shape, it can be made compact and the distribution cost can be reduced. (6) By contacting with water, it easily shrinks even in the temperature range of 0 to 50 ° C., so a special device for shrinking is not required, and the cost can be reduced. (7) Contact with water makes it soft and easy to remove. Due to the above effects, the moisture-shrinkable split cloth of the present invention is particularly suitable as a waste bag, sandbag material, tea bag material, and the like, which drain well.

Claims (2)

[Claims] 1. At least 10% due to humidity or moisture
A split cloth made of a stretch-molded product having the ability to shrink. 2. The stretch-molded product is a vinyl ester (co).
The split cloth according to claim 1, which is made of a partially hydrolyzed polymer.