JPH01201340A - Production of heat-resistant gas-permeable composite sheet - Google Patents

Abstract

PURPOSE:To obtain the title sheet improved in heat resistance, a function of restoring shape by heat, gas permeability, odorlessness, feeling and mechanical strengths, by hot-pressing a specified oriented film with a meshed sheet and repeating the heating and cooling of the obtained sheet. CONSTITUTION:An oriented film (A) is obtained by uniaxially or biaxially orienting a film obtained by mixing 45-70wt.% ethylene/propylene/diene copolymer (a) with 30-60wt.% ethylene/vinyl acetate copolymer (b) and 5-15wt.% filler (c) at a draw ratio of 1.5 or above and molding the resulting mixture. Component A is hot-pressed with a meshed sheet (B) preferably a (non)woven fabric under a pressure of 1.0-10kg/cm<2> at a temperature on the side of component B of 80-150 deg.C and a temperature on the side of component A of 75-95 deg.C to fix the component A with component B and to thermally shrink component A to make it microporous, and the assemblage is heated to a temperature at which component A does not flow, cooled and further subjected to a plurality of such heating/cooling cycles in which the heating temperature is raised stepwise by 50 deg.C to crosslink component A while keeping it microporous.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for producing a heat-resistant, breathable composite sheet, which has particularly high heat resistance, has a shape recovery function due to heat, is odorless, and is soft. The present invention relates to a method for producing a breathable composite sheet that has a soft texture and high mechanical strength.

[Conventional technology]

Conventionally, breathable films were made by kneading polyolefin resin with inorganic fillers, melt-molding it into a film shape, and making it into a film.
Those made porous by axial or biaxial stretching are used. In such a breathable film, fine fractures occur starting from the inorganic filler due to stretching, thereby forming pores with a pore size of about 1 to 4 μm.

The airflow rate of such a breathable film is 4500g/m'
・It is about a day. However, in -axial stretching, the tear strength in the stretching direction and the tensile strength in the transverse direction are extremely low due to anisotropy due to molecular orientation, and in biaxial stretching, the stretching ratio is low and air permeability is poor. Furthermore, due to the stiffness peculiar to stretched films, there is a problem in that they have a feel like gritty paper and are not suitable for applications requiring soft g.

In addition, a method of manufacturing a flexible porous film by adding the same kind of low melting point polymer, rubbery polymer, olefin thermoplastic elastomer, etc. to polyolefin resin along with an inorganic filler has been proposed, but the air permeability is not sufficient. In addition, there was a problem that the film strength was poor.

For this reason, various proposals have been made to impart flexibility to stretched breathable films made of polyolefin resins and inorganic fillers. For example, JP-A-60257221 discloses a mixture of 100 parts by weight of a polyolefin resin, 25 to 400 parts by weight of a filler, a liquid or waxy hydrocarbon polymer, or a mixture of the hydrocarbon polymer and an epoxy group-containing organic compound. This disclosure discloses a method for producing a porous film with excellent flexibility by melt-extruding a composition consisting of parts by weight and biaxially stretching the obtained film.

Furthermore, JP-A No. 62-10141 discloses a method for producing a porous film or sheet, which comprises stretching a film or sheet obtained by melt-molding a composition containing a polyolefin resin, a filler, and a triglyceride. are doing.

Further, JP-A-62-27438 discloses a method for producing a breathable film by stretching in at least one direction a film made of a composition of 42 to 87 volume % of a polyolefin resin and 58 to 13 volume % of an inorganic filler. The polyolefin resin is linear low density polyethylene 50-9
5% by weight of branched low-density polyethylene and 50 to 5% by weight of branched low-density polyethylene; The present invention discloses a method for producing a breathable film, which comprises blending 3 to 25 parts of a fatty acid ester based on 100 parts by weight of the composition.

However, since all of the above breathable films are obtained by stretching, they are thin and have poor mechanical strength.
It is often necessary to use it in conjunction with other materials. Therefore, secondary processing is required, which has the disadvantage of increasing the price.

Furthermore, since it does not contain a rubbery polymer, its flexibility is insufficient, and the desired soft feel cannot be obtained.

Therefore, the present inventor first stretched a film made of a crystalline polyolefin, a rubbery polymer, and a filler uniaxially or biaxially to form a stretched film, and then stretched the stretched film and the mesh-like sheet. hot-pressing at a temperature equal to or higher than the film's heat shrinkage start temperature to fix the stretched film to the mesh-like sheet and heat-shrink it;
A patent application has been filed for a method for producing a breathable composite film, which is characterized by making the film microporous.
(Patent application No. 62-170497).

This method heat-shrinks the stretched film and a mesh-like sheet made of woven fabric or non-woven fabric by hot-pressing the stretched film while fixing it to the mesh-like sheet, so the resulting composite film has excellent air permeability and is integrally formed. It is strongly reinforced by a mesh-like sheet fixed to the
High mechanical strength. Moreover, because of this structure, the composite film does not suffer from inferior tear strength even when it is formed from a -axis-oriented stretched film. Furthermore, since it contains a large amount of rubbery polymer, the composite film has the advantage of being highly flexible and having a soft feel.

[Problem that the invention seeks to solve]

However, recently there has been a demand for breathable composite films to have heat resistance so that they will not burn even if they come into contact with direct cigarette flames or the like. To improve heat resistance,
It is good to crosslink the ethylene-propylene-diene copolymer or ethylene-vinyl acetate copolymer in the film, but simply heat treatment will cause the film to melt and fluidize.
There is a problem that microporosity is lost. Moreover, there is a problem in that odor is generated during heating. It is also possible to crosslink the film simply by irradiating it with electron beams without heating, but when using an ethylene-vinyl acetate copolymer with a high vinyl acetate content, molecular cleavage caused by electron beam irradiation may cause crosslinking. There is a problem that a strong odor (acetic acid odor) is generated.

Therefore, an object of the present invention is to provide a method for producing a breathable composite sheet that has high heat resistance, no odor, has an excellent soft feel, and has high mechanical strength.

[Means for solving problems]

As a result of intensive research in view of the above objectives, the present inventors have developed a method by hot-pressing a stretched film of a specific composition and a mesh-like sheet, repeating heating and cooling several times, and gradually increasing the heating temperature. The inventors have discovered that the film can be sufficiently crosslinked, imparting good heat resistance to the breathable film and preventing odor, and have come up with the present invention.

That is, the method for producing a heat-resistant breathable composite sheet of the present invention involves the production of an ethylene-propylene-diene copolymer and an ethylene-propylene-diene copolymer.
A film containing a vinyl acetate copolymer is stretched uniaxially or biaxially to form a stretched film, and the stretched film and a mesh-like sheet are hot-pressed to fix the stretched film to the mesh-like sheet. The process of heating and cooling the film to a temperature at which it does not become fluid is repeated several times, and at this time, the heating temperature is gradually increased as the heating and cooling process progresses to the latter stage. The film is crosslinked while maintaining the microporosity of the film.

The ethylene-propylene-diene copolymer (EPOM) used in the present invention generally contains 60 to 70% by weight of ethylene,
30-40% by weight of propylene and 1-10% by weight of diene
This is the percentage of Here, the diene includes non-conjugated cyclic dienes such as Te, norbornenes, and cyclopentadines, and non-conjugated linear dienes such as 1.4-hexadiene. The Mooney viscosity of this EPDM is 45~
The temperature is preferably about 70°C (127°C). Further, in order to enhance the crosslinking effect by electron beam irradiation, which will be described later, it is preferable that the ethylene content is 60% by weight or more.

As the ethylene-vinyl acetate copolymer, one having an ethylene:vinyl acetate weight ratio of 93 to 70:30 is generally used. The vinyl acetate content is preferably 7.0% by weight or more.

Further, in the present invention, it is preferable to use a filler together with the above-mentioned polyethylene-propylene-diene copolymer and ethylene-vinyl acetate copolymer in order to make microporosity easier and to obtain blocking resistance.

Filling materials include talc, calcium carbonate, ceracola,
Carbon black, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, calcium phosphate,
aluminum hydroxide, zinc oxide, magnesium hydroxide,
Calcium oxide, magnesium oxide, titanium oxide, alumina, mica, shirasu balloon, zeolite, clay silicate, cement, silica hneem, mica powder, etc. can be used, but talc is particularly preferred. The average particle size of the filler is 5 μm or less, preferably 1 to 3 μm.

The above ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer and, if necessary, a filler are uniformly melt-kneaded to form a composition. In the present invention, 45 to 70% by weight of ethylene-propylene-diene copolymer,
It is preferable to knead 30 to 60% by weight of ethylene-vinyl acetate copolymer and 5 to 15% by weight of filler, particularly 40 to 70% by weight of ethylene-propylene-diene copolymer.
, 30 to 60% by weight of ethylene-vinyl acetate copolymer,
Preferably, the filler content is 5 to 15% by weight.

If the amount of ethylene-vinyl acetate copolymer is too small, the adhesive strength with the mesh-like sheet and the air permeability tend to decrease.
On the other hand, if the amount is too high, the composite sheet tends to lose its soft feel.

Note that heat stabilizers, ultraviolet stabilizers, antistatic agents, pigments, fluorescent agents, etc. may be added to the ethylene-propylene-diene copolymer and ethylene-vinyl acetate copolymer according to conventional methods.

The composition comprising the ethylene-propylene-diene copolymer, the ethylene-vinyl acetate copolymer, and the filler is uniformly kneaded using, for example, a Banbury mixer-1 twin-screw kneader.

For molding the film, any known method such as an inflation method using a circular die or a T-die method using a T-die can be used as appropriate.

The stretching may be either uniaxial or biaxial stretching, and in the case of -axial stretching, roll stretching may be used, and either -stage stretching or multistage stretching may be used. In addition, in the case of biaxial stretching, a tenter method is used,
Either sequential stretching or simultaneous stretching may be used. The stretching ratio is 1
．． It is 5 times or more, preferably 3 to 4 times. The thickness of the stretched film is generally about 30 to 80 μm, preferably 35 to 45 μm.

At the stretched film stage, there is substantially no air permeability. This is thought to be due to the high content of rubbery polymer.

The mesh-like sheet used in the present invention may be of any material as long as it has large enough voids (pores) to serve as a support for the breathable film and has sufficient mechanical strength, such as woven fabrics, non-woven fabrics, knitted fabrics, etc. Examples include papers, porous sheets, etc., and preferred mesh-like sheets include nonwoven fabrics such as spunbond, gauze, and other plain woven fabrics. The nonwoven fabric does not need to be made of long fibers, and may be made of short fibers intertwined or point welded.

It is necessary that the mesh-like sheet does not substantially melt or shrink during the hot pressing process described below. Therefore,
Generally, the melting point or secondary transition point of the mesh-like sheet needs to be at least 20° C. higher than that of the stretched film.

Hot compression bonding between a stretched film and a mesh-like sheet is generally carried out at a temperature of 80 to 150°C on the mesh-like sheet side and 75 to 95°C on the stretched film side, and at a temperature of 1.0 to 10 kg/cuf.
It is preferable to carry out the process at a pressure of . The temperature and pressure of hot pressing will vary somewhat depending on the composition of the stretched film and the type of mesh-like sheet, but if the temperature and pressure are too low, the stretched film and mesh-like sheet will not be sufficiently bonded, and if the temperature and pressure are too high, the adhesion will be poor. The waterproofness of the composite sheet decreases. Particularly preferable hot pressing conditions are that the mesh-like sheet side is 110 to 13
0℃, film side 85~95℃ and pressure 5~10K
g/cffl.

The hot press bonding between the stretched film and the mesh-like sheet is preferably carried out using heated rolls, as will be described in detail later. In this case, instead of pressing the stretched film and the mesh-like sheet one by one, the mesh-like sheet may be sandwiched between two stretched films, or conversely, the stretched film may be sandwiched between two mesh-like sheets. You can also

Furthermore, the present invention is characterized in that after hot-pressing the stretched film and the mesh-like sheet, heating and cooling processing is repeated a plurality of times. In this case, the heating temperature is increased stepwise as the process progresses from the first heating/cooling process to the latter heating/cooling process. This is because when the thermocompression-bonded film is heated to a high temperature in one stage, it melts and becomes fluidized, and its microporosity is lost.

Therefore, in the first stage heating and cooling process, it is necessary to keep the heating temperature below the fluidization temperature of the film, which is usually 70°C.
It is preferable to set it as -90 degreeC. There is no particular restriction on the heating time, but if it is too long, the microporosity may be lost, albeit gradually, so it is generally preferred to be within 60 seconds. This heat treatment crosslinks and stabilizes the unstable active groups in the resin, which not only improves heat resistance but also provides the advantage of preventing odor from occurring.

Cooling after heating is preferably performed by lowering the temperature to 30° C. or lower. Although the effect of this cooling step is not necessarily clear, it has been found that if the next heating step is performed without cooling, the microporosity of the film is lost. Therefore, it is necessary to cool down after heating in each step.

The heating temperature is increased stepwise as the latter heating/cooling process progresses, and the range of increase is generally preferably 50° C. or less. This is because if the temperature is increased more than 50 DEG C., melt fluidization occurs due to insufficient crosslinking of the film.

On the other hand, it is not economical to make the temperature increase range too small, so in practice it is preferable to repeat the heating and cooling step in stages with a temperature increase range of 20 to 40°C.

The number of times this heating and cooling step is repeated and the heating temperature vary depending on the composition of the stretched film, the type of mesh sheet, etc.; It is preferable to perform heating and cooling in three stages, heating to 80 °C in the first stage, 100 °C in the second stage, and 120 °C in the third stage for 60 seconds or less, and cooling at each stage to 30 °C or lower. . In addition, when using a woven fabric made of natural m fibers such as cotton fabric, the first stage
It is preferable to heat to 0°C, 120°C in the second stage, 160°C in the third stage, and 200°C in the fourth stage for 60 seconds or less, and cool down to 30°C or less at each stage.

Furthermore, in the present invention, electron beam irradiation can be performed after performing at least one heating and cooling step.

This electron beam irradiation further crosslinks the ethylene-propylene-diene copolymer and ethylene-vinyl acetate copolymer that constitute the film, improving heat resistance and preventing odor from occurring. In this case, the electron beam irradiation dose is generally 5 to 20! , 1 r a d is suitable.

In the present invention, the above-mentioned crosslinking agent that promotes crosslinking is not used, but the gel fraction after crosslinking is 65 to 95% by weight.
in the high range of

As mentioned above, the breathable composite sheet obtained by the method of the present invention has high heat resistance because its film layer is crosslinked by thermal energy and/or electron beams.

Therefore, it is difficult to perform sewing by thermal welding.

Therefore, it is preferable to carry out welding sewing using the following method.

(1) After welding and sewing the product (for example, gloves) into the shape of a product (eg, gloves) by high-frequency welding or the like, crosslinking treatment is performed.

(2) A non-crosslinked film (for example, an unstretched film) is sandwiched between the sheets, and this is used as an adhesive layer and welded.

(3) Preheat the high-frequency electrode and weld it.

A sheet crosslinked with a radiation dose of 5 to 20 Mrad can be completely bonded by heating the electrode mold to a temperature of 130° C. or higher.

[For production]

In the present invention, the stretched film is made of an ethylene-propylene-diene copolymer, an ethylene-vinyl acetate copolymer, and a filler if necessary, and since it is fixed to the fibers of the mesh sheet by the hot pressing process, the Looking at the stretched film portion in the gap between the two, the periphery is fixed by the fibers. When heat shrinkage occurs in the stretched film portion, the mm frame hardly changes, so the stretched film portion ends up being stretched due to the heat shrinkage. As a result, ventilation holes are formed in the film at the filler, and there is also a difference in heat shrinkage between the soft and hard segments, resulting in minute voids and partial fractures at the junctions between the film and the fibers. Vent holes are formed by peeling or peeling.

After the stretched film is hot-pressed onto a mesh-like sheet, heating and cooling are repeated multiple times, and the heating temperature is gradually increased from low to high temperatures to reduce air permeability due to melting and fluidization of the stretched film. (Disappearance of microporosity)
Heat crosslinking can be carried out while preventing this. This is because partial crosslinking occurs during the first heating and cooling step, raising the melt-fluidization temperature of the film, so that the film can be heated at a higher temperature in the next step without fluidizing it. As a result, the degree of layer crosslinking can be increased, and by repeating this process, a sufficient degree of crosslinking can finally be achieved without causing fluidization.

Further, even better crosslinking can be achieved by using electron beam irradiation in combination. At this time, an odor is generated due to the cutting of polymer molecular chains, but there is no problem if the irradiation is from 5 to 20 Mrad.

〔Example〕

FIG. 1 is a schematic diagram showing an example of an apparatus suitable for carrying out hot pressing according to the method of the present invention. This hot press bonding apparatus includes a roll 3 for cooling and heat-setting the stretched film 1, and a guide roll (
It has a preliminary roll) 4.4', a metal heating roll 5, a pressure fixing roll 6, and a cooling roll 7.8. The gap between the heating roll 5 and the pressure fixing roll (silicone rubber roll to which the film does not stick) 6 can be adjusted as appropriate so as to apply the desired pressure.

In this embodiment, mesh-like sheets 2 and 2' are hot-pressed on both sides of one sheet of stretched film 1, but when using only one mesh-like sheet, simply feed the mesh-like sheet 2'. It is better not to pay.

In addition, in order to have a structure in which a mesh-like sheet is sandwiched between stretched films, the stretched film l and the mesh-like sheet)
2.2' can be simply replaced.

The details of the breathable composite sheet obtained by hot-pressing the stretched film 1 to the mesh-like sheet 2 in this manner are shown in FIG.

The stretched film 1 is made of fibers of the mesh-like sheet 2! 21, so the stretched film portion 11 in the gap between the fibers
Looking at it, it can be seen that the periphery is fixed by the fibers 21. If heat shrinkage occurs in the stretched film portion 11, then! , 1!21 hardly changes, so the stretched film portion 11 ends up being stretched due to heat shrinkage.

FIG. 3 is an enlarged cross-sectional view showing an example of the state in which the hot-pressed stretched film 10 and the mesh-like sheet 1121 are fixed. Since the fibers 21 are embedded and fixed in the film 10, they act as a fixing frame when the stretched film is thermally shrunk, and minute gaps are created between the fibers 21 and the film IO.

FIG. 4 is an enlarged sectional view showing an example of a composite film formed by hot pressing a mesh-like sheet sandwiched between two stretched films 10 and 10'. Similar to the example shown in FIG. 3, the fibers 21 of the mesh-like sheet act as a fixing frame during heat shrinkage of the stretched film, and the fibers 21 of the mesh-like sheet act as a fixing frame during heat shrinkage of the stretched film. ! A minute gap is created between 21 and the film 10.10'.

Note that the fibers of the mesh-like sheet do not need to be completely buried as shown in FIG. 3, but may be partially buried as long as they are sufficiently fixed to the stretched film.

FIG. 5 is a schematic diagram showing an example of an apparatus suitable for carrying out the heating and cooling step in the method of the present invention.

A composite sheet 50 formed by hot-pressing a stretched film and a mesh-like sheet through the hot-pressing process shown in FIG. 1 passes through a roll 51 and enters a first heating chamber 52 and a cooling chamber 53.

The composite sheet 50 is heated to a first temperature (for example, 70°C) in the heating chamber 52.
~90°C) and cooled to 30°C or lower in the cooling chamber 53. Thereafter, an electron beam is irradiated with an electron beam irradiation device 54, and heating and cooling are repeated in a heating chamber 52' and a cooling chamber 53'.

Finally, the obtained heat-resistant breathable composite sheet 50' is wound onto a reel 57 via guide rollers 55 and 56. Note that a heating and cooling process may be performed two or more times before electron beam irradiation.
Further, the heating and cooling step after irradiation may be performed multiple times or may be omitted. Furthermore, the electron beam irradiation may be omitted by simply performing the heating and cooling process multiple times.

The method of the present invention will be further explained in detail by the following specific examples.

In addition, in each example, the air permeability is 645.16 mm.
This value is expressed as the time (seconds) required for 100 cc of air to pass through a composite sheet with a circular hole area of . In addition, the heat resistance is 2. The composite sheet was placed at a distance of 0cm with the film surface facing the heater side, and the evaluation was made by observing whether a change occurred in 60 seconds.

Example l Ethylene-vinyl acetate copolymer (vinyl acetate content 28
weight%) 35 parts by weight and 5 parts of ethylene-propylene-diene copolymer (Vistaron 3708, manufactured by Nippon Unicar)
A composition consisting of 5% by weight and 10% by weight of talc (average particle size 5 μm) was melt-kneaded using a twin-screw kneader and formed into a film by a water-cooled inflation method. The obtained film having a thickness of 120 μm was uniaxially stretched three times while heating it to 50° C. to obtain a stretched film. The air permeability of this stretched film was approximately 0.

This stretched film and a blended plain woven fabric of polyester fibers and nylon fibers (manufactured by Toyobo, weight 18 g/m') were fed at a speed of 5 m/min to the device shown in Fig. 1, and Temperature in °C and 5kg/CII! Hot compression bonding was carried out under pressure conditions of .

Next, it was heated at 80°C for 30 seconds, cooled to 30°C, further heated at 100°C for 30 seconds, cooled to 30°C, heated again at 120°C for 30 seconds, and cooled to 30°C.

The thickness, weight, air permeability and heat resistance of the composite sheet thus obtained were measured. The results were as shown in Table 1.

Example 2 In Example 1, cotton woven fabric (33
g/m'), and heating and cooling after hot press bonding was performed as follows.

First stage: heating at 80°C for 60 seconds, cooling to 30°C.

Second stage: heating at 120°C for 60 seconds, cooling to 30°C.

Third stage: heating at 160°C for 60 seconds, cooling to 30°C.

4th stage: heating at 200°C for 60 seconds, cooling to 30°C.

A composite sheet was created under these conditions, and the same process as in Example 1 was carried out.
The same measurements were performed. The results are shown in Table 1.

Example 3 In Example 2, gauze (30 g/m
A composite sheet was prepared under the same conditions except that 1) was used, and the same measurements as in Example 1 were performed. The results are shown in Table 1.

Example 4 The film obtained in Example 1 was heated at 50°C by 3.0 times.
Biaxially stretched to 0 times, the two obtained stretched films were sandwiched between the cotton woven fabric of Example 2 and the polyester woven fabric, and hot press bonded under the same conditions as in Example 1. Next, Example 2
The film was crosslinked by heating and cooling under the same conditions as above. Table 1 shows the measurement results of the thickness, weight, and air permeability of the composite sheet obtained.

Example 5 The composite sheet hot-pressed in Example 1 was heated at 80°C for 6
A heat-resistant breathable composite sheet was prepared by heating for 0 seconds and then irradiated with an I Q Mrad electron beam, and the same test was conducted. The results are shown in Table 1.

Note that no odor was observed during electron beam irradiation.

Example 6 A composition consisting of EPDM/EVA (weight ratio: 60/40) was melt-kneaded using a twin-screw kneader to obtain a blown film. The obtained 30 μm film was uniaxially stretched 4.5 times while heating it to 50° C. to obtain a stretched film with a thickness of 35 μm.

The air permeability of this stretched film was zero. This stretched film and 100% cotton plain woven fabric (manufactured by Toyobo ■, 80g)
/m') was supplied at a speed of 5 m/min in the apparatus shown in Figure 1, and hot compression bonding was performed at a fabric side roll temperature of 125°C, a film side roll temperature of 95°C, and a pressure of 8 kg/cj. . Then heat to 100°C for 30 seconds and 3 seconds for 30 seconds.
After cooling to 0° C., electron beam irradiation was further performed at 10 Mrad. The durability of the composite sheet thus obtained is the first
As shown in the table.

Comparative Example 1 In Example 1, the film was crosslinked by heating to 120°C. The resulting composite sheet had completely lost its air permeability.

Comparison Example 2 In Example 1, after hot pressing of the stretched film and woven fabric,
Before the first stage heating and cooling process, electron beam irradiation (20 Mar
) A composite sheet was produced under the same conditions as in Example 1, except that The air permeability and heat resistance of the obtained composite sheet were almost the same as in Example 1, but a strong acetic acid odor was generated during electron beam irradiation.

〔Effect of the invention〕

In the method of the present invention, by appropriately adjusting the stretching ratio of the film, hot pressing temperature, pressure, etc., it is possible not only to obtain the desired air permeability but also to heat and cool the film multiple times after hot pressing. Since the film is crosslinked in this step, a breathable composite sheet with good heat resistance can be produced.

Therefore, the breathable composite sheet obtained can withstand heat of 200° C. or higher, and is unlikely to burn out even if it comes into contact with direct flame such as a cigarette. It also has a heat-induced shape recovery function, so wrinkles and shrinkage that occur during washing and use can be corrected by ironing.

Further, it is possible to prevent the generation of odor during the manufacturing process, particularly during electron beam irradiation, and a comfortable working environment can be maintained.

In addition to the above-mentioned characteristics, the heat-resistant breathable composite sheet obtained by the method of the present invention has excellent breathability and mechanical strength. do not have. Also, since it contains a large amount of rubbery polymer, it is highly flexible and has a soft feel.

Such heat-resistant and breathable composite sheets can be used not only for various types of clothing, especially special protective clothing such as simple fire protection clothing and protective clothing for work, but also for automobiles. It can be widely used for interior parts of airplanes and airplanes, building materials such as wallpaper, and interior goods such as carpets, tablecloths, and curtains.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the hot pressing process of the method of the present invention, FIG. 2 is a partially enlarged view of a composite sheet bonded by thermocompression, and FIG. FIG. 4 is an enlarged cross-sectional view showing the relationship between the film and fibers of the composite sheet bonded by thermocompression. FIG. FIG. 2 is a schematic diagram showing an example of an apparatus for performing the heating and cooling process. 1...Stretched film 2.2'...Mesh-like sheet 4.4'...Guide roll 5...Heating roll 6...Crimping fixed rolls 10, 10'...Film 21... Mesh-like sheet fiber 50...
- Composite sheet 50'... Heat-resistant breathable composite sheet 52, 52'
... Heating chambers 53, 53' ... Cooling chamber 54 ... Electron beam irradiation device Applicant: Tonen Petrochemical Co., Ltd. Representative: Patent attorney Takaishi Tachibana Ma Fig. 1 Fig. 2 Procedure: Tadashi Neichi Manufactured 4 (Spontaneous) July 278, 1988 1 Indication of the case Patent Application No. 25200 of 1988 2 Name of the invention Method for manufacturing heat-resistant breathable composite sheet 3 Relationship with the person making the amendment Name of the patent applicant Tonen Oil Co., Ltd. Kagaku Co., Ltd. 4 Agent 5 Date of amendment order Showa Year Month Day (Shipping mortar) 7 Contents of amendment 1, Mei IB, page 20, line 12, “(preparation roll)” is corrected to “(preheating roll)” do. 2. On the last line of page 23, "35 heavy hanging part" is corrected to "35% by weight." 3. On page 26, line 15 of the same page, "30 trends" is corrected to "80 trends."

Claims (9)

[Claims] (1) A film containing an ethylene-propylene-diene copolymer and an ethylene-vinyl acetate copolymer is uniaxially or biaxially stretched to form a stretched film, and the stretched film and a mesh-like sheet are hot-stretched. The stretched film is fixed to the mesh-like sheet by pressure bonding and heat-shrinked, thereby making the film microporous, and then the process of heating and cooling the film to a temperature at which it does not become fluid is repeated multiple times, and at that time, A method for producing a heat-resistant breathable composite sheet, characterized in that the heating temperature is increased stepwise as the heating and cooling process progresses to the latter stage, thereby crosslinking the film while maintaining its microporosity. (2) In the method according to claim (1), the ethylene-propylene-diene copolymer contains 45 to 70% by weight,
The ethylene-vinyl acetate copolymer is 30 to 60% by weight
, and a method characterized in that the filler is 5 to 15% by weight. (3) In the method according to claim (1) or (2),
A method characterized by uniaxially or biaxially stretching the film by 1.5 times or more. (4) The method according to any one of claims (1) to (3), wherein the mesh sheet is a nonwoven fabric or a woven fabric. (5) The method according to any one of claims (1) to (4), characterized in that the stretched film and the mesh-like sheet are hot-pressed using a heat roll. (6) In the method according to any one of claims (1) to (5), the hot pressure bonding is performed so that the mesh sheet side has a
A method characterized by carrying out at a temperature of 150°C, a temperature of 75 to 95°C on the film side, and a hot pressing pressure of 1.0 to 10 kg/cm^2. (7) The method according to any one of claims (1) to (6), characterized in that in the plurality of heating and cooling steps, the heating temperature is successively increased by 50°C or less. (8) The method according to any one of claims (1) to (7), characterized in that the cooling temperature in the plurality of heating and cooling steps is 45°C or less. (9) A film containing an ethylene-propylene-diene copolymer and an ethylene-vinyl acetate copolymer is uniaxially or biaxially stretched to form a stretched film, and the stretched film and a mesh sheet are heated together. The stretched film is fixed to the mesh-like sheet by pressure bonding and heat-shrinked, thereby making the film microporous, and then heated to a temperature at which the film does not become fluidized and then cooled at least once, and then 5 A method for producing a heat-resistant breathable composite sheet, characterized in that it is further crosslinked by irradiation with an electron beam of ~20 Mrad.