JP2001270051A - Laminate and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate which has a sufficient bonding strength between a fluorine resin layer and a thermoplastic resin layer or a rubbery layer of not less than 1.2 N/mm, is easily manufactured and does not cause any problem of safety in work and cost and to provide its manufacturing method. SOLUTION: A laminate obtained by laminating a thermoplastic resin layer or a rubbery layer on a fluorine resin layer and its manufacturing method are characterized in that there exists a hydroxyl group of not less than 1.4% introduced by a reduced pressure plasma treatment and an oxygen-enriched air treatment on the surface of the fluorine resin layer to be bonded to the thermoplastic resin layer or the rubbery layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate in which a thermoplastic resin layer or a rubber layer is formed on a fluororesin layer. More specifically, the present invention relates to a fluororesin layer and a thermoplastic resin layer or a rubber layer. 1.2 N / mm adhesive strength with the layer
The above relates to a firmly bonded laminate and a method for producing the same.

[0002]

2. Description of the Related Art Fluororesins having excellent corrosion resistance to chemicals and gasoline are used for various resin products. In many cases, fluororesins are not used alone but formed from these fluororesins. It is used as a laminate in which the formed fluororesin layer and a layer formed of, for example, a thermoplastic resin or rubber are laminated. Such a laminate has both excellent characteristics of a fluororesin and mechanical characteristics such as abrasion resistance of a thermoplastic resin or the like.

[0003] In manufacturing the above-mentioned laminate, not a general fluororesin but a special fluororesin in which a bonding surface layer to be bonded to a thermoplastic resin layer or the like is modified is used. This is because general fluororesin has extremely low adhesiveness to other constituent materials, and thus, for example, does not adhere firmly only by an adhesive treatment using an adhesive. Further, a laminate used for a special purpose such as contact with a fuel or a chemical such as gasoline has a higher adhesive strength (1.
2 N / mm or more). This is because there is a possibility that the fluororesin layer and the thermoplastic resin layer or the like may be separated by contact with gasoline or the like.

[0004] Examples of conventional fluororesins in which the bonding surface layer is modified include, for example, the following two types of fluororesins. (1) Fluororesin whose resin surface is etched with a metal sodium complex (for example, “Ind. Eng. C.
hem. , 50, 329, 1958 "). (2) Fluororesins having irregularities formed on the resin surface by sputtering (for example, those described in JP-B-58-25742).

[0005]

However, the above-mentioned modified fluororesin has various problems. That is, the fluororesin modified with the metal sodium complex of the above (1) has a problem that the adhesive strength of a laminate using the fluororesin decreases with time. In particular, when ultraviolet rays are irradiated, the above-mentioned adhesive strength is significantly reduced. Furthermore, since the above-described modification method using a metal sodium complex solution requires steps such as immersion and washing of the fluororesin in the metal sodium complex solution, there is a problem that the treatment step is long and complicated, and the metal sodium complex Solutions also have human safety concerns.

[0006] In addition, the use of an adhesive having low fluidity deteriorates the adhesiveness of the fluororesin subjected to the sputtering treatment of the above (2), and the unevenness of the resin surface formed by the sputtering treatment is easily reduced by abrasion. There is a problem of disappearing. For this reason, when manufacturing a laminated body using this sputtered fluororesin, it is necessary to pay close attention to its handling, and the production efficiency of the laminated body is reduced.

Further, these conventional modified fluororesins are:
There is a common problem that the adhesiveness is poor when a thermoplastic resin or the like is directly laminated without using an adhesive. For example,
In the case of manufacturing a laminate using a fluororesin and a thermoplastic resin, there is a method in which the thermoplastic resin is melted by heating. According to this heat fusion method, the steps of applying and drying the adhesive are omitted, so that the manufacturing process of the laminate is simplified, and it is necessary to use an organic solvent for dissolving the adhesive. This has the advantage that the working environment becomes safer. However, as described above, since the conventional modified fluororesin has poor adhesiveness by the heat fusion method, the above-mentioned advantages of the heat fusion method cannot be fully utilized.

[0008] As described above, the conventional modified fluororesin does not sufficiently improve the adhesiveness, and thus a laminate obtained by using the modified fluororesin does not have a practically usable adhesive strength. In the manufacture of the laminate manufactured by such a conventional technique, there are problems such as work safety, manufacturing efficiency, and cost. However, as described above, a laminate in which a thermoplastic resin layer or a rubber layer is laminated on a fluororesin layer has excellent characteristics. Therefore, it is strongly desired to solve the above problem. .

The present invention has been made in view of such circumstances, and has a sufficiently high adhesive strength of 1.2 N / mm or more between a fluororesin layer and a thermoplastic resin layer or a rubber layer, and is easy to manufacture. Accordingly, it is an object of the present invention to provide a laminate and a method for producing the same without problems of work safety and cost.

[0010]

According to the present invention, there is provided a laminate comprising a fluororesin layer and a thermoplastic resin layer or a rubber layer formed on the fluororesin layer. Alternatively, a laminate in which a hydroxyl group is present at a rate of 1.4% or more in a surface layer of the bonding of the fluororesin layer to the rubber layer by a reduced-pressure plasma treatment and an oxygen-enriched air treatment is referred to as a first gist. A method for producing a laminate in which a thermoplastic resin layer or a rubber layer is formed by laminating, after performing a reduced-pressure plasma treatment on a bonding surface layer portion of the fluororesin layer to the thermoplastic resin layer or the rubber layer. The oxygen-enriched air is brought into contact with the bonding surface of the fluororesin layer so that the hydroxyl groups are present at a ratio of 1.4% or more. The preparation of the laminate forming the fat layer or rubber layer as the second aspect.

In other words, the present inventors have conducted a series of studies focusing on the modification of a fluororesin for the purpose of improving the adhesion of the fluororesin to a thermoplastic resin or the like. In the process, the mechanism of the development of the adhesiveness of the fluororesin was examined in detail, and it was found that the adhesiveness was exhibited when a hydroxyl group was present in the surface layer of the fluororesin. This will be described using a fluororesin and a polyamide resin as an example. As shown in FIG. 3, if a hydroxyl group is present in the fluororesin, the hydroxyl group (—OH) and the amide bond (—NHC)
A hydrogen bond occurs between the oxygen atom (-C = O) in O-) and adhesiveness is developed. Therefore, when further research was conducted on the relationship between the hydroxyl group of the fluororesin surface layer and the development of the adhesive property, it was found that in the laminate composed of the fluororesin layer and the thermoplastic resin layer or the rubber layer, the thermoplastic resin layer or the rubber layer was used. It was ascertained that the bonding strength of the laminate was 1.2 N / mm or more when the hydroxyl group was present at 1.4% or more in the bonding surface layer portion of the fluororesin layer. Then, by the reduced pressure plasma treatment, it was found that it is possible to easily and safely introduce the specific proportion of the hydroxyl groups into the bonding surface layer portion of the fluororesin without using special equipment and the like, and together with the above findings. Arrived at the present invention. According to the present invention, a high-performance laminate having a sufficient adhesive strength can be provided easily and at low cost.

In the present invention, the amount of hydroxyl groups (%) in the bonding surface layer portion of the fluororesin layer refers to a value measured by photoelectron spectroscopy (ESCA), and the ratio of hydroxyl groups refers to the bonding surface layer of the fluororesin. The ratio of the number of oxygen atoms in a hydroxyl group (-OH) to the total number of atoms excluding hydrogen atoms in a part.

[0013]

Next, the present invention will be described in detail.

The laminate of the present invention is obtained by laminating a fluororesin layer and a thermoplastic resin layer or a rubber layer, and a hydroxyl group is formed on a bonding surface layer portion of the fluororesin layer to the thermoplastic resin layer or the rubber layer. It is present in 1.4% or more.

The above-mentioned fluororesin layer can be obtained by forming a normal fluororesin in a layered form and then performing a modification treatment described later on the bonding surface layer portion to the thermoplastic resin layer and the like.

Examples of the fluororesin forming the fluororesin layer include copolymers of ethylene and tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and ethylene. Copolymer of ethylene and chlorotrifluoroethylene (ECTFE), copolymer of vinylidene fluoride and tetrafluoroethylene, copolymer of vinylidene fluoride and hexafluoropropylene, and copolymer of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene Copolymer, polytetrafluoroethylene (PTF
E), a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), a copolymer of tetrafluoroethylene and perfluoroalkylvinyl ether (PF
A), a copolymer of vinylidene fluoride and tetrafluoroethylene, and a copolymer of vinylidene fluoride and hexafluoropropylene. These can be used alone or
More than one type is used together. Among them, workability, flexibility,
It is preferable to use ETFE because of its excellent durability.

Preferably, a filler is added to the fluororesin for the purpose of improving its physical properties. Examples of such a filler include titanium oxide, barium sulfate, calcium carbonate, silica, carbon black, magnesium silicate, aluminum silicate, zinc oxide, alumina, calcium sulfate, aluminum sulfate, calcium hydroxide, and aluminum hydroxide. , Talc, molybdenum dioxide, whiskers, staple fibers, graphite, metal powder, silica sand, pumice powder, slate powder, mica powder, asbestos, glass spheres and the like. The compounding ratio of the filler is usually set to 30 parts or less, preferably to 5 to 20 parts with respect to 100 parts by weight (hereinafter abbreviated as "part") of the fluororesin.

It is preferable that the fluororesin is provided with conductivity. That is, as described above, in a laminate used for a special purpose such as contact with a fuel such as gasoline or the like, if static electricity is generated in the laminate, there is a risk that the fuel may catch fire. The purpose of imparting conductivity to the fluororesin can be achieved, for example, by blending a conductive agent with the fluororesin. Examples of the conductive agent include carbon black and fine stainless metal fibers. The proportion of the conductive agent is preferably set in the range of 0.5 to 30 parts based on 100 parts of the fluororesin. When the conductive agent is blended in this range,
The volume efficiency of the fluororesin layer of the obtained laminate is 10 ¹⁰ Ω
-Cm or less, it is possible to discharge static electricity to the outside of the laminate and release it, and in the laminate for special use, accidents such as ignition of fuel such as gasoline are prevented beforehand.

Next, the thermoplastic resin layer and the rubber layer will be described.

The material for forming the thermoplastic resin layer is not particularly limited, and examples thereof include a polyamide resin and a polyester resin. Among these, it is preferable to use a polyamide resin because of its excellent mechanical properties such as abrasion resistance. Examples of the polyamide resin include nylon 6, nylon 66, nylon 11, nylon 12, and the like. These may be used alone or in combination of two or more. Among these, nylon 11 and nylon 12 which are particularly excellent in the characteristics of wear resistance and moldability.
Is preferred.

A plasticizer may be added to the polyamide resin, if necessary, to improve processing characteristics and flexibility. Examples of the plasticizer include sulfonamides and oxybenzoic esters. The mixing ratio of this plasticizer is usually 20 parts per 100 parts of the polyamide resin.
Part or less.

The material for forming the rubber layer is not particularly limited. For example, epichlorohydrin rubber (CO), an equimolar copolymer of epichlorohydrin and ethylene oxide (commonly called ECO, also known as CHC), acrylonitrile butadiene rubber ( NBR), a blend rubber of NBR and polyvinyl chloride (PVC) (NBR / PV
C), chloroprene rubber (CR), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CP)
E), ethylene-propylene-diene rubber (EPDM)
And the like. Among them, ECO, NBR, NB are used because of their excellent properties such as heat resistance and ozone resistance.
R / PVC and CSM are preferred, and EC is particularly preferred.
O.

Next, the method for producing the laminate of the present invention will be described.
A method for producing a sheet-like laminate will be described as an example based on the schematic process diagram of FIG.

As shown in FIG. 1, the method of manufacturing the sheet-like laminate 1 includes a step (a) of preparing a sheet-like fluororesin layer 2.
And a step (b) of subjecting the bonded surface layer portion 2a of the sheet-shaped fluororesin layer 2 to low-pressure plasma treatment 4, and, if necessary, the sheet-shaped fluororesin layer 2 bonded surface portion 2 after the low-pressure plasma treatment
The method includes a step (c) of bringing oxygen-enriched air 5 into contact with a, and a step (d) of laminating the thermoplastic resin 3 or the rubber layer 3 on the sheet-like fluororesin 2 bonding surface layer 2a.

First, a sheet-like fluororesin layer 2 as shown in FIG. 1A is formed. This can be formed by blending various additives such as a filler in the above-mentioned fluororesin as required at a predetermined ratio, and extruding the mixture with an extruder or the like to form a sheet.

Next, as shown in FIG. 1B, a reduced pressure plasma treatment 4 is performed on the bonding surface layer 2a of the sheet-like fluororesin 2. The reduced-pressure plasma treatment 4 is not particularly limited as long as it can introduce a hydroxyl group into the sheet-like fluororesin layer 2 bonding surface layer 2a.
It is preferable to select low-temperature plasma processing such as glow discharge as such reduced-pressure plasma processing. This is a method in which low-temperature plasma treatment is a simple method, and a method in which the surface layer can be modified without deteriorating the excellent properties inherent to the fluororesin such as corrosion resistance to chemicals and gasoline. That's why. The low-temperature plasma processing is specifically described below.
In this method, the object to be processed (sheet-like fluororesin layer 2) is exposed to plasma generated by glow discharge generated when a high voltage is applied to the electrode (for example, “Low-temperature plasma chemistry, edited by Keiichiro Hozumi, Chemistry, special edition 11
No. 1, Nankodo Shuppan, published in 1976 ").

The conditions of the low-pressure plasma treatment such as the low-temperature plasma treatment are such that hydroxyl groups can be introduced at a rate of 1.4% or more into the sheet-like fluororesin layer 2 bonding surface layer 2a. There is no particular limitation. The general conditions are as follows.

Atmosphere gas type: H ₂ , He, N ₂ , Ne, Ar
Etc. inert gas. Atmospheric gas pressure: 10 to 1000 Pa High frequency power supply (RF) output: 10 to 300 W Processing time: 1 second to 5 minutes

The preferred range of the above conditions is as follows.

Atmosphere gas type: H ₂ , N ₂ , Ar Atmospheric gas pressure: 10 to 300 Pa RF output: 10 to 300 W Processing time: 1 second to 1 minute

The reduced pressure plasma processing is performed using, for example, a reduced pressure plasma processing apparatus 12 shown in FIG. In this reduced-pressure plasma processing apparatus 12, electrodes 7a and 7b are arranged in a closed chamber 6 so as to face each other, and a high-frequency power source 8 is connected to the electrodes 7a and 7b. At predetermined positions of the closed chamber 6, an inlet 9 and an outlet 10 for an atmospheric gas are provided, and communicate with each other through a pipe to an atmospheric gas supply device (not shown) and a vacuum pump (not shown), respectively. ing. In the figure, arrows 11 and 13 indicate the inflow and outflow states of the atmospheric gas, respectively.

The low-pressure plasma processing using the low-pressure plasma processing apparatus 12 is performed, for example, as follows. That is, as shown, the sheet-like fluororesin layer 2 is disposed between the electrodes 7a and 7b in the chamber 6. On the other hand, the air in the chamber 6 is exhausted from the outlet 10, and then the atmospheric gas is introduced from the inlet 11 to bring the inside of the closed chamber 6 into a predetermined reduced pressure state. In this state, the high-frequency power source 8 operates the electrode 7 under the above-mentioned predetermined conditions.
a, 7b to generate plasma between the electrodes 7a, 7b. After the plasma treatment, when taken out into the air, a hydroxyl group is introduced into the bonding surface layer 2a of the sheet-like fluororesin layer 2. The introduction ratio of the hydroxyl group can be adjusted by the above-mentioned various conditions of plasma generation.

In the present invention, the bonding surface layer portion 2a of the fluororesin 2 refers to a bonding surface portion of the fluororesin 2 and a portion from this to a certain depth (thickness). This is because when the fluororesin layer and the thermoplastic resin layer or the like are bonded, the part involved in the bonding is not only the surface part but also a part having a certain thickness including the surface part.

Next, if necessary, the sheet-like fluororesin 2 bonding surface layer 2a subjected to the low-pressure plasma treatment 4 is
A process of contacting oxygen-enriched air with an increased oxygen concentration (hereinafter, also appropriately referred to as “oxygen-enriched air treatment”) is performed.

The above-described oxygen-enriched air treatment is usually carried out by charging the above-mentioned reduced-pressure plasma-treated fluororesin into a treatment tank having an oxygen-enriched air atmosphere inside. The oxygen content of the oxygen-enriched air is usually from 20 to 90% by volume, preferably from 20 to 90% by volume at 20 to 25 ° C.
７０70% by volume. The oxygen-enriched air preferably has a water vapor pressure of 1 to 40 mmHg, particularly preferably 4 to 36 mmHg.

The reason why the oxygen-enriched air treatment is performed as required is as follows. That is, it is a certain fact that when the fluororesin is subjected to the reduced-pressure plasma treatment, it is certain that the hydroxyl group is introduced into the resin surface layer portion, but the introduction amount may be insufficient. This is because the oxygenated air treatment makes it possible to introduce a sufficient amount of hydroxyl groups.

Although the mechanism of introducing a hydroxyl group by the above-described reduced-pressure plasma treatment and the mechanism of introducing a hydroxyl group by the subsequent oxygen-enriched air treatment cannot be clearly explained, the present inventors have conducted a series of studies on the laminate. It is presumed from the findings obtained in that the hydroxyl groups are introduced into the fluororesin through the following two routes.

First, as a first route, when a low-pressure plasma treatment is performed on a fluororesin, carbon atoms in the surface portion of the fluororesin are activated to generate carbon radicals. It is conceivable that the oxygen and hydrogen atoms contained therein are bonded to introduce a hydroxyl group into the fluorine resin surface layer. Further, as a second route, the carbon radicals in the surface layer of the fluororesin generated by the low-pressure plasma treatment dissociate the moisture in the atmospheric gas to generate hydroxyl groups, and the hydroxyl groups are bonded to the carbon radicals to form fluorine groups. A route for introducing a hydroxyl group into the resin surface layer is conceivable.

In the case of the first route, since the amount of oxygen atoms in the atmospheric gas for performing the low-pressure plasma treatment is usually very small, there is a possibility that the introduction of hydroxyl groups into the surface layer of the fluororesin may be insufficient. Then, after the low-pressure plasma treatment, oxygen-enriched air is brought into contact with the fluororesin surface layer, whereby oxygen can be effectively bonded to carbon radicals on the fluororesin surface layer, and a sufficient amount of hydroxyl groups is introduced. It will be possible to do so. Here, as described above, the oxygen-enriched air has a water vapor pressure of 1 to 40.
mmHg is preferable, and particularly preferably 4 to 36 mmHg.
mmHg.

In addition, the introduction of hydroxyl groups into the surface layer of the fluororesin is considered not to pass separately through each of the above-mentioned routes, but simultaneously through the above-mentioned two routes. Is preferably brought into contact with oxygen-enriched air having a high relative humidity.

Next, after such reduced pressure plasma treatment 4 and oxygen-enriched air treatment 5, the sheet-like fluororesin layer 2
A thermoplastic resin layer 3 or a rubber layer 3 is formed on the bonding surface layer 2a.

First, the case of forming the above-mentioned thermoplastic resin layer 3 will be described. First, the above-mentioned thermoplastic resin is formed into a sheet by extrusion molding or the like to prepare a sheet-like thermoplastic resin layer. Heat and melt. The conditions for the heating and melting are appropriately determined depending on the melting point of the thermoplastic resin and the like. Then, the sheet-like fluororesin layer 2 bonding surface layer 2
The above-mentioned sheet-shaped thermoplastic resin layer 3 that has been heated and melted is disposed on top of “a” such that the heat-fused surface thereof faces the fluororesin layer 2 bonding surface layer 2a. Then, pressure 0.1 ~
Under the conditions of 30 kgf / cm ² and time of 0.5 to 10 minutes,
The two sheets are cooled to room temperature while being pressed by a press machine, and the two sheets are bonded to each other. Thus, the sheet-like laminate 1 in which the thermoplastic resin layer 3 is formed on the fluororesin layer 2 can be manufactured.

On the other hand, when a rubber layer is formed, a sheet-like unvulcanized rubber is prepared in the same manner as in the case of forming the above-mentioned thermoplastic resin layer, and this is used for the above-mentioned sheet-like fluororesin layer 2 bonding surface layer portion 2a. Place on top. Then, pressure 0.1-30k
Under a condition of gf / cm ² and a time of 0.5 to 10 minutes, both sheets are pressed by a press machine, and the sheet-like unvulcanized rubber is pressed to the sheet-like fluororesin layer 2. Then, by vulcanizing the sheet-like unvulcanized rubber, the sheet-like laminate 1 in which the rubber layer 3 is laminated on the fluororesin layer 2 can be produced. The rubber vulcanization conditions are appropriately determined depending on the type of rubber used and the like.
C. x 20 to 90 minutes. Further, at the time of the pressing, a heat treatment may be performed to perform press vulcanization.
The conditions of the press vulcanization are as follows: the pressure is the same as that of the press, and the rubber vulcanization is appropriately determined depending on the type of rubber. By performing this press vulcanization,
The press compression and rubber vulcanization can be performed in one step, and the production efficiency of the sheet-like laminate is improved.

In the laminate of the present invention, a reduced pressure plasma treatment and, if necessary, an oxygen-enriched air treatment are performed on the bonded surface layer portion of the fluororesin layer, and an adhesive is applied to the bonded surface layer portion. A resin layer or a rubber layer may be formed. As described above, when the adhesive is used, the adhesive strength between the two layers in the laminate of the present invention is further improved. Examples of the adhesive include a polyester adhesive and the like, and in addition, a silane coupling agent can also be used. The effect of improving the adhesive strength by applying the adhesive is remarkable when the rubber layer is formed.

A sheet-like laminate is produced through such a series of steps (see FIG. 1). However, the laminate of the present invention is not limited to a sheet-like form, but may be a fluororesin layer and a thermoplastic resin. The form is not limited as long as the layer or the rubber layer is laminated. Examples of the laminate in a form other than the sheet form include a laminate in a container form such as a fuel tank or a chemical tank. In this case, a configuration is adopted in which a fluororesin layer is formed as an inner layer that comes into contact with gasoline or chemicals, and a thermoplastic resin layer or the like is formed on the outer peripheral surface of the inner layer. Furthermore, since the laminate using the fluororesin has excellent corrosion resistance to fuels and chemicals such as gasoline, it can be used as a fuel hose for automobiles by extruding into a tube shape, and can be used as a fuel pipe for automobiles and the like. It can be used for parts to be used, members used for manufacturing chemicals, and the like.

As described above, by performing the reduced pressure plasma treatment and, if necessary, the oxygen-enriched air treatment under the above-mentioned predetermined conditions, the hydroxyl group is added to the bonding surface layer portion of the fluororesin by 1.4.
% Or more will be introduced. As aforementioned,
This amount of hydroxyl groups refers to a value measured by ESCA. This E
SCA is a method of analyzing a fluororesin-bonded surface layer using a photoelectron spectrometer (for example, ES-200, manufactured by Kokusai Electric Inc.). The measurement conditions are, for example, as follows.

Excited X-ray: Al, Kα _1,2 ray (1486.6 eV) X-ray output: 10 kV, 20 mA Temperature: 20 ° C. Vacuum: 3 × 10 ⁻⁸ Torr

In the ESCA described above, it is preferable from the viewpoint of measurement accuracy that the hydroxyl group in the surface layer of the fluororesin joint is not directly detected but detected by chemically modifying the hydroxyl group. Describing the chemical modification of the hydroxyl group, a silicon-containing reagent (HMDS) represented by the following general formula (1) is brought into contact with the surface layer of the fluororesin junction. Then, in the surface layer of the fluororesin layer, the following reaction formula (2)
Occurs, and the hydroxyl group is replaced with silicon (Si). Then, by measuring the amount of silicon by ESCA, the amount of hydroxyl groups in the surface layer of the fluororesin junction can be determined.

[0049]

Embedded image

[0050]

Embedded image

Next, examples will be described together with comparative examples.

[0052]

Examples 1 to 13 and Comparative Examples 1 to 3 The following Tables 1 to 3 were applied to the bonding surface layer of sheet-like fluororesin (ETFE).
Under reduced pressure plasma treatment. Next, a sheet-like thermoplastic resin (nylon 12), one surface of which is heated and melted at 240 ° C., is disposed on the joint surface layer so that the heat-fused surface and the joint surface layer face each other.
While pressing both sheets with a press under the conditions of kgf / cm ² and 3 minutes, the sheets were cooled to room temperature to produce a sheet-like laminate. Regarding the size of this sheet-like laminate, the thickness of the fluororesin layer was 0.2 mm and the thickness of the thermoplastic resin layer was 2.
0 mm.

Examples 1 to 1 thus obtained
3. With respect to the sheet laminates of Comparative Examples 1 to 3, the adhesive strength between the fluororesin layer and the thermoplastic resin layer, and the amount of hydroxyl groups in the fluororesin layer bonding surface layer were examined. The results are also shown in Tables 1 to 3 below. In addition, the said adhesive strength and the hydroxyl group amount were investigated by the method shown below.

[Adhesive Strength] The adhesive strength was measured by a 90 ° peel test. That is, as shown in FIG. 7, a part of the sheet-like laminated body 1 is peeled off, and the peeled end of the fluororesin layer 2 is moved at a speed of 50 mm using a strograph (manufactured by Toyo Seiki Co., Ltd.).
Per minute, the peel strength was measured by pulling the thermoplastic resin layer 3 in the direction perpendicular to the thermoplastic resin layer 3 (arrow A), and this peel strength was taken as the adhesive strength.

[Amount of hydroxyl group] ESCA measurement was performed on the surface layer of the release surface of the sheet laminate subjected to the above adhesive strength test on the fluororesin layer side, using the above-mentioned HMDS, replacing the hydroxyl group and silicon. . The ESCA measurement conditions at this time are as shown below. Excited X-ray: Al, Kα _1,2 ray (1486.6 eV) X-ray output: 10 kV, 20 mA Temperature: 20 ° C. Vacuum: 3 × 10 ⁻⁸ Torr

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

From the above Tables 1 to 3, the sheet-like laminate of the example product in which the amount of hydroxyl groups in the surface layer portion of the fluororesin layer is 1.4% or more has excellent adhesive strength of 1.2 N / mm or more. It can be seen that it has. In contrast, the sheet-like laminate of the comparative example product in which the amount of hydroxyl groups in the surface layer portion of the fluororesin layer joined was less than 1.4% had an adhesive strength of less than 1.2 N / mm. In particular, in the sheet-like laminate of Comparative Example Product 3 not subjected to the reduced-pressure plasma treatment, the fluororesin layer and the thermoplastic resin layer did not adhere.

Example product 11 subjected to an adhesive strength test
ESCA measurement was performed on the surface layer of the release surface of the sheet-like laminate of Example 1 to examine the functional groups present in the fluororesin-bonded surface layer. As a result, as shown in the graph of FIG.
The presence of hydrogen bonds was confirmed.

Then, the above Examples 1 to 13 and Comparative Examples 1 to
From the results of 3, the relationship between the amount of hydroxyl groups (%) in the surface layer of the fluororesin layer and the adhesive strength of the fluororesin layer and the thermoplastic resin layer was examined. The results are shown in the graph of FIG.
As shown in the drawing, the hydroxyl group is 1.
It can be seen that when 4% or more was present, the adhesive strength was 1.2 N / mm or more. In addition, the above Examples 1 to 13,
From the results of Comparative Examples 1 to 3, it was found that the RF output of the reduced pressure plasma treatment, the gas pressure (in a reduced pressure state), the amount of hydroxyl groups (%) in the surface layer of the fluororesin layer joint, and the adhesive strength between the fluororesin layer and the thermoplastic resin layer were determined. The relationship between the people was examined. The results are shown in the graph of FIG. In the graph, ○ in the graph indicates that the adhesive strength is 1.2 N / mm or more, X indicates that the adhesive strength is less than 1.2 N / mm, and the contour lines indicate the fluororesin layer bonding. Shows the amount (%) of hydroxyl groups in the surface layer.
As shown in the figure, within a range of predetermined reduced pressure plasma processing conditions,
It can be seen that the amount of hydroxyl groups in the surface layer of the fluororesin joint was 1.4% or more, and the adhesive strength was 1.2 N / mm or more.

[0062]

Embodiment 14 After applying a reduced-pressure plasma treatment to the bonding surface layer portion of a fluororesin (ETFE) with an atmosphere gas of Ar, RF output of 100 W, reduced-pressure condition of 266 Pa and processing time of 5 seconds, an oxygen content of 50 vol. % (20 ° C.) and 70% relative humidity RH. Next, a sheet-like thermoplastic resin (nylon 12), one surface of which is heated and melted at 240 ° C., is placed on the joint surface layer so that the heat-fused surface and the joint surface layer face each other, and a pressure of 2 k is applied.
While pressing both sheets with a press under the conditions of gf / cm ² and 3 minutes, the sheets were cooled to room temperature to produce a sheet-like laminate. The size of the sheet-like laminate is such that the thickness of the fluororesin layer is 0.2 mm and the thickness of the thermoplastic resin layer is 2.0 mm.
mm.

With respect to the sheet-like laminate of Example product 14 thus obtained, the adhesive strength between the fluororesin layer and the thermoplastic resin layer and the amount of hydroxyl groups in the surface layer of the fluororesin layer joint were examined by the above-mentioned method. Was. As a result, the amount of hydroxyl groups in the surface layer portion of the fluororesin layer joined was 3.0%, and the adhesive strength was 2.7 N / mm. From this, it can be said that by performing the oxygen-enriched air treatment, it was possible to sufficiently introduce a hydroxyl group into the surface layer of the fluororesin, and accordingly, the adhesive strength was significantly improved.

[0064]

Examples 15 to 17 The fluororesin layer and the thermoplastic resin layer were formed by using the materials shown in Table 4 below and the conditions shown in the same table.
A sheet-like laminate was formed by the same operation as in Example 1 above. Regarding the size of the sheet-like laminate, the thickness of the fluororesin layer is 0.2 mm and the thickness of the thermoplastic resin layer is 2.0 mm. With respect to the sheet-like laminates of Examples 15 to 17 thus obtained, the adhesive strength and the amount of hydroxyl groups were examined by the above-described method. The results are also shown in the table.

[0065]

[Table 4]

From Table 4 above, even when a laminate is formed using various materials, the surface area of the fluororesin layer bonding surface has a hydroxyl group of 1.4.
%, The adhesive strength becomes 1.2 N / mm or more.

[0067]

Examples 18 to 21 A fluororesin layer and a rubber layer were formed by the above-mentioned rubber layer forming method under the materials and conditions shown in Table 5 below to produce a sheet-like laminate.
The pressing condition of the sheet-like unvulcanized rubber pressure bonding is 20k.
gf / cm ² for 0.5 minute. In the sheet-like laminate, the thickness of the fluororesin layer is 0.2 mm and the thickness of the rubber layer is 2.0 mm. With respect to the sheet-like laminates of Examples 18 to 21 thus obtained, the adhesive strength and the amount of hydroxyl groups were examined by the above-described method. The results are also shown in the table.

[0068]

[Table 5]

From Table 5 above, even when a laminate is formed using a rubber layer, the surface area of the fluororesin layer-bonded surface layer has a hydroxyl group content of 1.4%.
It can be seen that the adhesive strength becomes 1.2 N / mm or more if present.

[0070]

Embodiment 22 After applying a reduced-pressure plasma treatment to a bonding surface layer portion of a fluororesin (ETFE) with an atmosphere gas of Ar, an RF output of 100 W, a reduced pressure condition of 266 Pa, and a processing time of 5 seconds, an adhesive (silane-based) was used. Coupling agent) was applied. Then, a sheet-like N is placed on the joining surface layer.
The BR unvulcanized rubber was pressed with a press under the conditions of a pressure of 20 kgf / cm ² and 0.5 minutes. Then, at a temperature of 160 ° C,
A vulcanization treatment was performed under the conditions of a time of 45 minutes to produce a sheet-like laminate. The size of the sheet-like laminate is such that the thickness of the fluororesin layer is 0.2 mm and the thickness of the rubber layer is 2.0 mm.
mm.

When the adhesive strength between the fluororesin layer and the rubber layer of the sheet-like laminate of Example product 22 thus obtained was examined by the above method, the adhesive strength was found to be 3.5 N / mm. there were. From this, it can be said that the adhesive strength was significantly improved by performing the adhesive treatment.

[0072]

As described above, the laminate of the present invention is formed by laminating a thermoplastic resin layer or a rubber layer on a fluororesin layer. Hydroxyl groups are present at a rate of 4% or more. in this way,
The modified fluororesin having a specific proportion or more of hydroxyl groups in the bonding surface layer comes to adhere to the thermoplastic resin or rubber with a high adhesive force of 1.2 N / mm or more due to the hydrogen bond formed from the hydroxyl groups. . Therefore, the laminate of the present invention does not cause separation of the two layers, and has excellent durability. Further, if a polyamide resin layer having excellent mechanical properties such as abrasion resistance is formed as the thermoplastic resin layer, the durability of the laminate becomes more excellent. Also,
If an adhesive (silane-based coupling agent, polyester-based adhesive, etc.) is applied to the surface layer of the fluororesin layer to form a thermoplastic resin layer or a rubber layer, the adhesive strength between the two layers can be further increased. Be improved.

In the method for producing a laminate according to the present invention, a thermoplastic resin layer or a rubber layer is formed after applying a reduced pressure plasma treatment to a bonding surface layer portion of a fluororesin layer to introduce a hydroxyl group. The above-mentioned reduced-pressure plasma treatment is a simple method that does not require special equipment and devices, and is a method that does not use substances harmful to the human body such as an organic solvent. It is a low and safe manufacturing method. In addition, if the oxygen-enriched air treatment is further performed after the reduced-pressure plasma treatment, it becomes possible to introduce a sufficient amount of hydroxyl groups into the bonding surface layer portion of the fluororesin, and the adhesive strength of the obtained laminate is remarkably excellent. become. Then, when forming the thermoplastic resin layer or the rubber layer, if the thermoplastic resin or the like is heated and melted and directly fused to the fluororesin layer bonding surface layer portion, the laminated body is not subjected to an adhesive application step or the like. Can be produced, and the production efficiency is improved.

[Brief description of the drawings]

FIG. 1A is a configuration diagram showing a fluororesin layer,
(B) is an explanatory view showing a state in which a reduced pressure plasma treatment is performed on the fluororesin layer bonding surface portion, and (c) is a diagram in which oxygen-enriched air is brought into contact with the fluororesin layer bonding surface portion after the decompression plasma treatment. It is explanatory drawing which shows the state made to be made, (d)
FIG. 3 is a configuration diagram showing a state in which a thermoplastic resin layer or a rubber layer is laminated and formed on the fluororesin-bonded surface layer.

FIG. 2 is a configuration diagram illustrating an example of a reduced pressure plasma processing apparatus used in the present invention.

FIG. 3 is an explanatory diagram showing a state in which a hydrogen bond exists between a polyamide resin and a fluororesin.

FIG. 4 is a graph showing the presence of hydrogen bonds.

FIG. 5 is a graph showing the relationship between the amount of hydroxyl groups and adhesive strength.

FIG. 6 is a graph showing the relationship among reduced pressure plasma processing conditions, hydroxyl group content, and adhesive strength.

FIG. 7 is an explanatory diagram showing an implementation state of an adhesive strength test.

Claims (5)

[Claims] 1. A laminate in which a thermoplastic resin layer or a rubber layer is laminated on a fluororesin layer, and a reduced pressure plasma is applied to a bonding surface portion of the fluororesin layer to the thermoplastic resin layer or the rubber layer. A laminate characterized in that hydroxyl groups are present at a rate of 1.4% or more by the treatment and the oxygen-enriched air treatment. 2. The laminate according to claim 1, wherein a thermoplastic resin layer or a rubber layer is directly formed on the fluororesin layer. 3. The laminate according to claim 1, wherein the thermoplastic resin layer is a polyamide resin layer. 4. A method for producing a laminate in which a thermoplastic resin layer or a rubber layer is laminated on a fluororesin layer, wherein a bonding surface of the fluororesin layer to the thermoplastic resin layer or the rubber layer is formed. After performing low-pressure plasma treatment, oxygen-enriched air is brought into contact with the bonding surface layer of the fluororesin layer so that hydroxyl groups are present at a ratio of 1.4% or more. A method for producing a laminate, comprising forming a thermoplastic resin layer or a rubber layer thereon. 5. The steam pressure of the oxygen-enriched air is from 1 to 40 m
The method for producing a laminate according to claim 4, which has a mHg.