JPH02215842A - Water-swelling porous sheet - Google Patents

Abstract

PURPOSE:To obtain the title sheet with gas permeability, moisture permeability and water-swelling property and useful for a water-stopping material, an anti- sweating material, a waterproof material, etc., by forming it with a highly water-absorbing resin, a linear low-density PE resin, a filler and furthermore a specified rubber-contg. resin compsn. CONSTITUTION:A water-swelling porous sheet is manufactured by molding a rubber-contg. resin compsn. consisting of a highly water-absorbing resin (e.g. powdery saponified ethylene-vinyl ester-acrylate), a linear low-density PE resin (e.g. a copolymer of ethylene with butene) and a filler (e.g. clay) and furthermore an ethylene-alpha-olefin copolymer or an ethylene-alpha-olefin-nonconjugated diene copolymer into a sheet, drawing the obtd. sheet and/or extracting the soluble filler and furthermore perforating it mechanically with ultrafine needles. This sheet exhibits gas permeability, moisture permeability and water-swelling property and can be used for a water-stopping material, an anti-sweating material such as a wall material for anti-sweating, a water absorbing sheet, roof substrate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a water-swellable porous sheet, specifically, it has air permeability, moisture permeability, and water-swellability, and is used as a water-cleaning material and for preventing dew condensation. The present invention relates to water-swellable porous sheets used for dew condensation prevention materials such as wall materials, water-absorbing sheets, V-roof base materials, and the like.

(b) Conventional technology When a porous sheet formed by stretching is used as a stopper, a dew condensation prevention material such as a dew condensation prevention wall material, a water absorption sheet, and a roof base material, due to the manufacturing method, it is oriented in the stretching direction and has elasticity. As a result, the seams between the porous sheets used as waterproofing materials or the joints between the porous sheets and other sealing members are completely waterproof. They are incompetent.

Therefore, a water-swellable foam containing a superabsorbent resin or a water-swellable rubber elastic body has been proposed as a sealing material. (Unexamined Japanese Patent Publication No. 59-148646, Unexamined Japanese Patent Publication No. 59-1
89180).

In addition, water-swellable rubber products have been proposed that have improved water absorption performance by using both a filler and a super absorbent resin in the rubber base material (Japanese Patent Laid-Open Nos. 59-145230 and 61-62539).
Publication No.).

(e) Problems to be Solved by the Invention However, none of the above materials have moisture permeability or air permeability, so these materials can be used as dew prevention materials such as wall materials for preventing dew condensation or as roof base materials. When used, there are problems such as humidity and heat being trapped indoors and causing discomfort, especially during high temperature and humidity such as during the rainy season.

In addition, because they do not have moisture permeability or air permeability, when these materials are used as walls, the moisture inside the walls will not be released to the outside and the structural materials of the walls will rot or the strength will deteriorate. This results in a decrease in durability.

Furthermore, even when these materials are used as roofing materials, the moisture in the attic cannot be released to the outside, resulting in problems such as poor durability.

The present invention has been completed in view of the above-mentioned problems, and has water-swelling properties in terms of air permeability and moisture permeability, and is suitable for use in dew prevention materials such as stoppers, dew condensation prevention wall materials, water-absorbing sheets, and roof base materials. The object of the present invention is to provide a water-swellable porous sheet that can be suitably used for.

(d) Means for solving the 81 problems The inventor of the present invention has made the following findings as a result of intensive studies to achieve the above object.

That is, by forming a water-swellable porous sheet using a specific rubber-mixed resin composition containing a super-absorbent resin, this sheet has holes that prevent water or air from interacting with the water-absorbing resin. Since the contact area is large, the water absorption rate (including moisture in the air) is extremely fast, so even a small amount of super absorbent resin has a large water absorption effect.Moreover, this sheet has elasticity and increases in volume by absorbing water. It has been found that because of the expansion, the adhesion between the water-swellable porous sheets or at the joint between the water-swellable porous sheet and another sealing material becomes good and an excellent sealing effect can be obtained.

On the other hand, even if this water-swellable porous sheet absorbs water once, the superabsorbent resin will release water when it dries.Moreover, this water release is done through the pores, so the water release rate is fast. Furthermore, it has been found that since excellent moisture permeability and air permeability can be obtained, it can be suitably used particularly as a dew condensation prevention material such as a dew condensation prevention wall material and a roof base material.

The present invention has been completed based on the above findings.

In the water-swellable porous sheet of this NIB requirement 1, a super absorbent resin, a linear low density polyethylene resin and a filler,
Furthermore, ethylene-a olefin copolymer or ethylene-a olefin copolymer
(a) It is formed from a rubber mixed resin composition consisting of an olefin non-conjugated tzene copolymer.

The super absorbent resin used in the present invention has a weight of 30% of its own weight.
It is not particularly limited as long as it has a water absorption capacity of 100 times or more, especially 100 times or more, and has a high affinity with the linear low-density polyethylene resin described below, but specifically,
For example, saponified products of ethylene-vinyl ester-acrylic acid ester, cross-linked products of acrylic acid-acrylate copolymers, cross-linked products of alkali metal salts of starch-acrylic acid graft polymers, reactions of polyvinyl furfur and maleic anhydride. Examples include alkaline salts of ethylene-vinyl ester-acrylic acid, saponified products of acrylic acid-vinyl alcohol copolymers, and sodium acrylic acid polymers. Saponified acid esters are desirable because they have excellent heat resistance, weather resistance, and the like.

In addition, when using the superabsorbent resin in powder form, the average particle size is 30 μm or less, preferably 0.1 to 10 μm, from the viewpoint of dispersibility and mixability with other components.
Ideally, it should be within the scope of theory.

In the water-swellable porous sheet of the present invention, a linear low-density polyethylene resin is used as the resin component from the viewpoint of quality stability, productivity, processability, etc.

The above linear low density polyethylene resin is a copolymer of ethylene and a-olefin, and the a-olefin includes:
Examples include butene, hexene, octene, and the like.

In the present invention, a filler is added to the linear low-density polyethylene resin, and such fillers include calcium carbonate, talc, clay kaolin, silica, barium sulfate, kaolin sulfate, aluminum hydroxide, zinc oxide, Examples include calcium oxide, titanium oxide, alumina, mica, etc. Among these, clay is particularly preferred from the viewpoint of water swelling performance and chemical resistance.

The average particle size of the filler used is 30 .mu.m or less, preferably in the range of 0.1 to 10 .mu.m.

If the particle size is too large, the through holes will become large and the mechanical strength of the obtained water-swellable porous sheet will decrease.
On the other hand, if it is too small, agglomeration will occur and dispersibility will be poor, which is not preferable.

In addition to the above-mentioned components, the above-mentioned linear low-density polyethylene resin may also contain additives that improve cross-linking properties and dispersibility of the filler, improve moldability and processability, or contain water-swellable porous materials obtained. In order to improve the functional strength of the sheet, an ethylene-a olefin copolymer or an ethylene-a olefin non-conjugated tzene copolymer is further blended.

The above-mentioned olefin terpolymer is not particularly limited as long as it is a rubber-like material with a number average molecular weight of 5,000 to 800,000, and typical examples include ethylene, α-olefin, and non-conjugated double bonds. A cyclic or acyclic copolymer (hereinafter referred to as EPDM) is used.

The above EPDM is ethylene, propylene or butene.
It is a terpolymer consisting of the polyene monomers listed below. Examples of the polyene monomers include cyclopentadiene, 1!5-cyclooctanediene,
-Cyclooctanezene, 1,6-cyclohexanoene, 1,7-cycloheptadiene, 1.5.9-cyclododecatriene, 1.4-cycloheptadiene, 1,4-
These include cyclohexanoene, 1,6-heptadiene, norbornatsuene, methylenenorbornene, ethylidenenorbornene, 2-methylpentanoene-1,4,1,5-hexadiene, methyl-tetrahydroindene, 1,4-hexanoene, and the like.

The copolymerization ratio of each monomer is preferably 30% of ethylene.
A terpolymer having a Mooney viscosity ML, *, (100° C.) of 1 to 60 is preferable, with a polyene content of 0.1 to 20 mol% and the remainder being α-olefin.

In forming the water-swellable porous sheet of the present invention, the above-mentioned super-absorbent resin, linear low-density polyethylene resin, and filler are used, as well as an ethylene-a olefin copolymer or ethylene-a, TI/fin nonconjugated tzene. A rubber mixed resin composition made of a copolymer is formed into a sheet, and the sheet obtained by combing is stretched and/or extracted with a soluble filler, and then mechanically perforated with a very fine needle.

The water-swellable porous sheet may contain commonly used antioxidants, ultraviolet stabilizers, antistatic agents, lubricants, fluorescent agents, etc., and may have a number average molecular weight of 1.
000 to 30,000 may be added.

Specific typical examples of the above-mentioned softeners include petroleum process oil, liquid paraffin, aliphatic oil, and low molecular weight plasticizers as low viscosity softeners, and polybutene and low molecular weight plasticizers as relatively high viscosity softeners. Examples include softeners such as polyisobutylene and liquid rubber.

In the water-swellable porous sheet according to claim 2, 100 parts by weight of the linear low-density polyethylene resin is mixed with 20 parts by weight of the super absorbent resin. ~20.0 parts by weight, filler 10-300fi
fii and ethylene-a olefin copolymer or ethylene-α olefin non-conjugated tzene copolymer 5 to 95 times 1
By using a rubber mixed resin composition with this blending ratio, the water absorption rate (including moisture in the air) is extremely fast.
In addition, this sheet has elasticity and expands in volume by absorbing water, so it has good adhesion between the water-swellable porous sheets or at the joint between the water-swellable porous sheet and other sealing material. Even if it absorbs water, the superabsorbent resin will release water when it dries, but this water release is done through the pores, so it is easy to release water. It is possible to obtain a water-swellable porous sheet that is fast, has high mechanical strength, and has excellent moisture permeability and air permeability.

In this case as well, antioxidants, ultraviolet stabilizers, antistatic agents, lubricants, fluorescent agents, and softeners may be added, as in the water-swellable porous sheet described above.

The water-swellable porous sheet according to claim 3 of the present application is formed by molding a rubber mixed resin composition into a sheet shape and stretching it in a pongee or biaxial direction, and this sheet is homogeneous as a whole. Moreover, since there is no variation, it is particularly suitable for use as a dew condensation prevention material such as a dew condensation prevention wall material, a water absorbing sheet, a roof base material, etc.

That is, a rubber mixed resin composition is molded into a film, and this is directly formed by stretching or stretching into a two-wheeled vehicle, or a porous sheet is obtained by stretching, and then this is treated with acid, alkali or water. It may also be formed by eluting a soluble filler.

In order to mold the above rubber mixed resin composition into a sheet shape, it is sufficient to use ordinary molding equipment and molding methods, and an inflatable molding machine, a T-die molding machine, etc. are suitably applied. The sheet is stretched in one or two directions to form a porous sheet, and this stretching may be carried out in a conventional manner using ordinary stretching equipment, such as roll stretching, simultaneous two-wheel stretching, sequential two-wheel stretching, etc. Stretching etc. are used.

In this stretching process, in the case of -axial stretching, the stretching rate is 100 to 400%, and in the case of biaxial stretching, the stretching rate is 10 to 200%, so that the obtained water a This is preferable from the viewpoints of the strength of the porous sheet and the size of the through holes, that is, air permeability, moisture permeability, and internal strength of the machine.

In particular, in the case of -axial stretching, if the stretching ratio is less than 100%, stretched parts and unstretched parts will coexist, resulting in non-uniform stretching, whereas if it reaches 400%, new parts may break during stretching. I don't like it because it is.

In addition, the said stretching ratio is the value calculated|required by the following formula.

] Also, special equipment is not required for mixing the super absorbent resin, linear low density polyethylene resin, filler, and ethylene-α olefin copolymer or ethylene-α olefin non-conjugated diene copolymer. , a known mixer is used, but in order to uniformly mix these materials and further improve the formability of the sheet, a mixer such as a mixing roll, a Banbury mixer, a twin-shaft mixer, or a Henschel mixer is used. It is preferable to use

(e) Effect The water-swellable porous sheet of the present invention has the above-mentioned welfare,
It is formed into a sheet using a predetermined rubber mixed resin composition containing a super absorbent resin, and is porous, so the contact area between water or air and the water absorbent resin is large. Therefore, the water absorption rate (including moisture in the air) is extremely fast, so even a small amount of super absorbent resin has a great effect.Moreover, this sheet has elasticity and expands in volume by absorbing water, so it is highly effective. This has the effect of providing good adhesion between the water-swellable porous sheets or at the joints between the water-swellable porous sheets and other sealing materials, resulting in an excellent sealing effect.

Furthermore, even if this water-swellable porous sheet absorbs water once, the superabsorbent resin releases water when it dries.Moreover, this water is released through the pores, so the water release rate is fast. Furthermore, since it has excellent moisture permeability and air permeability, it has the effect of being suitably used in water-stopping materials, dew condensation prevention materials such as dew condensation prevention wall materials, water absorbing sheets, roof base materials, and the like.

(f) Examples Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

Examples 1 to 3 As shown in Table 1, acrylic acid-
A vinyl alcohol copolymer (average particle size 10 μm) was used, linear low density polyethylene resin (MI2.O1 density 0.93), and EPDM as an olefin terpolymer.
(ethylene-propylene-ethylidene norbornene, Mooney viscosity 20, number average molecular weight 11,400,000), calcium carbonate as a filler (average particle size 2μ brocade, fatty acid treatment), and stearic acid as a lubricant in the proportions shown in Table 1. The mixture is sufficiently stirred and mixed, and the mixture is sufficiently kneaded using a twin-shaft wire machine (TEM-50, manufactured by Toshiba Machine Co., Ltd.) to obtain a rubber mixed resin composition, which is then granulated by a conventional method. .

The above-mentioned rubber mixed resin composition is formed into a sheet shape using an extrusion mill, and this is uniaxially stretched using a roll stretching machine.
A porous sheet was obtained.

In this case, the stretching conditions were a stretching temperature of 40° C., a stretching speed of 6 m/s+in, and the stretching ratio was adjusted to the values shown in Table 1 by changing the speed ratio of the rolls.

The obtained water-swellable porous sheet had no stretching unevenness and was entirely porous.

Table 1 shows the results of various characteristic tests of the water-swellable porous sheet obtained by Hidden.

(The following is a blank space) Comparative Example 1 A sheet formed from a rubber mixed resin composition (containing no superabsorbent resin at all) shown in Table 1 was stretched to obtain a porous sheet.

Comparative Example 2 (Blended composition) EPDM 100 parts by weight clay
100 parts by weight paraffin wax 30 parts by weight tS water-absorbing fat
60 parts by weight urea foaming agent 15 parts by weight urea foaming aid 15 parts by weight 1 part sulfur
1.5 parts by weight vulcanization accelerator
3 parts by weight zinc white
Table 12 shows the properties of the 5-layer, 11 parts.

Comparative Example 3 (Blended composition) Clay 100 weight 1 part ethylene
α-olefin non-conjugated tzene compound (EPDM)
1001! 1 part paraffin wax
30 parts by weight water absorbent resin
60 weight 1 part Crosslinking agent 2 parts Crosslinking accelerator 2 parts Zinc white
5 parts by weight or more of the blended composition a
- Mixed in a 45φ extruder and made into a sheet with 0.51
Extruded to thickness.

Its properties are shown in Table 2.

The above blended composition was kneaded with a roll and extruded into a sheet with a thickness of 0.51I11 using a 45φ extruder.

The obtained sheet was crosslinked and foamed in an oven at 170°C.

Table 2 Note 1) The stretching ratios shown in Table 1 are values determined by the following formula.

Note 2) Moisture permeability shown in Tables 1 and 2 is JISL
Moisture permeability in 1099? Measured using the bu method.

Note 3) The water absorption rates shown in Table fjS1 and Table 2 were determined using the following formula.

Water absorption rate = W'-W/WX100 (%) W: Weight before water absorption W': Weight after water absorption Note 4) The volume expansion coefficient shown in fjSim and Table 2 was determined by the following formula.

Volumetric expansion coefficient = S'-8/SXI 00 (%) S: Volume before water absorption So: Volume after water absorption Also, each example is used as a stopper, dew condensation prevention material such as dew condensation prevention wall material, water absorption sheet When used as a roof base material, this sheet has elasticity and expands in volume by absorbing water, so it is difficult to bond between the water-swellable porous sheets or between the water-swellable porous sheets and other sealing materials. It was observed that the adhesion was good in some areas and an excellent sealing effect was obtained.

On the other hand, the material of Comparative Example 1 has poor elasticity and almost no water absorption, and therefore does not expand in volume, so it is difficult to connect the water-swellable porous sheets with each other or between the water-swellable porous sheets and other sealants. It was confirmed that the adhesion was extremely poor and no sealing effect was observed at the joints with (~).

In addition, the material of Comparative Example 2 had a high water absorption rate and a high volumetric expansion coefficient, so it was found that the sealing effect was high, but the air permeability and moisture permeability were low. The reason for this is thought to be that there are fewer communicating holes.

Therefore, when the same dew condensation prevention test as in the above example was conducted, it was found that the dew condensation prevention effect was extremely poor and dew condensation occurred.

Furthermore, in Comparative Example 3, both the water absorption rate and the volumetric expansion rate were
It was observed that the moisture permeability was not only lower than that of Comparative Example 2, but also extremely low.

Therefore, it was found that the sealing effect and dew condensation prevention effect were also lower than those of Comparative Example 2.

([1) Effects of the Invention Since the present invention is configured as described above, it achieves the effects described below.

In the water-swellable porous sheet according to claim 1, a water-swellable porous sheet is formed using a specific rubber mixed resin composition containing a super absorbent resin, and this sheet has a porous Because it is water and air absorbent! Since the contact area with F-fat is large, the rate of water absorption (including moisture in the air) is extremely fast. Therefore, even a small amount of super-absorbent resin has a large effect. Furthermore, this F-fabric has elasticity and absorbs water. As a result, the volume expands, resulting in good adhesion between the water-swellable porous sheets or at the joints between the water-swellable porous sheets and other sealing materials, resulting in an excellent sealing effect. We have it.

Furthermore, even if this water-swellable porous sheet absorbs water once, the superabsorbent resin releases water when it dries.Moreover, this water is released through the pores, so the water release rate is fast. Furthermore, since excellent moisture permeability and air permeability can be obtained, it has the effect of being suitably used for dew stoppers, dew condensation prevention materials such as dew condensation prevention wall materials, water absorbing sheets, roof base materials, etc.

In the water-swellable porous sheet of claim 2, based on 100 parts by weight of linear low density polyethylene, 20 to 200 parts by weight of super absorbent resin, 10 to 300 parts by weight of photonic agent, and ethylene-a olefin. By using a rubber mixture U (formed from a pilgrimage composition) consisting of 5 to 95 parts by weight of a copolymer or an ethylene-α olefin nonconjugated tsene copolymer, The rate of water absorption (including moisture in the air) is extremely fast, and this sheet has elasticity and expands in volume by absorbing water, so the water-swellable porous sheets or water-swellable porous sheets At the joint between the sheet and other sealants, the adhesion is even better and an excellent sealing effect is obtained. Since water is released through the pores, the water release rate is fast, and it also has the effect of providing a water-swellable porous sheet with high mechanical strength and excellent moisture permeability and air permeability. .

Water of claim 3! A wettable porous sheet is formed by molding a rubber mixed resin composition into a sheet shape and stretching it into a shaft or two wheels, and this sheet is homogeneous throughout and has no variation. In particular, it has the effect of being suitably used as a dew condensation prevention material such as a dew condensation prevention wall material, a water absorbing sheet, a roof base material, etc.

Claims (3)

[Claims] (1) Water-swellable resin composition made of a rubber mixed resin composition consisting of a super absorbent resin, a linear low density polyethylene resin, a filler, and an ethylene-α olefin copolymer or an ethylene-α olefin non-conjugated diene copolymer. porous sheet. (2) The rubber mixed resin composition contains 100 parts by weight of linear low-density polyethylene resin, 20 to 200 parts by weight of super absorbent resin, 10 to 300 parts by weight of filler, and ethylene-α olefin copolymer or ethylene-α Claim 1 comprising 5 to 95 parts by weight of an olefin non-conjugated diene copolymer.
The water-swellable porous sheet described above. (3) The water-swellable porous sheet according to claim 1 or 2, which is formed by molding a synthetic resin composition into a sheet shape and stretching it uniaxially or biaxially.