JPH0415370A - Diaphragm - Google Patents

Abstract

PURPOSE:To secure the gasoline deteriorationproofness on a gasoline contact side and the freezing resistance on an air contact side by allowing the polymerization composition of the acrylic rubber of the rubber vulcanizate in each rubber layer on the gasoline contact side and the air contact side to satisfy the prescribed necessary conditions. CONSTITUTION:The polymerization composition of the acrylic rubber of the rubber vulcanizate in each rubber layer on a gasoline contact side and an air contact side is constituted so that the following conditions are satisfied. The former: total quantity of ACAS and AN = 24 - 88wt%, ACAS/AN(weight ratio = 1 - 7, the latter: total quantity of ACAS and AN = 34 - 80wt%, ACAS/AN(weight ratio) = 8 - 20. Rubber layers 3 and 5 are formed by coating the kneaded substance of the FR rubber compound on both the surfaces of a substrate cloth 1 on which adhesive treatment is applied, by using a calender roll, extruder, etc. In this case, the polymerization composition of the acrylic rubber for the use on the gasoline contact side and air contact side which satisfies the above-described necessary conditions is used, and vulcanization and punching-out are properly applied in this order on a shaped unvulcanized lamination sheet, and a diaphragm is obtained.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is characterized in that the rubber layer is formed of a rubber vulcanizate of so-called vinylidene fluoride modified acrylic rubber (hereinafter simply referred to as "specific ACMJ"), and when used, This relates to a diaphragm in which one side is in contact with gasoline and the other side is in contact with air.

This invention is particularly suitable as a diaphragm for devices such as fuel pumps and pressure regulators in automobile fuel circuit systems.

<Prior art> Here, as shown in FIG. 1, both sides of the base fabric 1 are covered with rubber layers 3
．． The explanation will be given by taking as an example a diaphragm 5, which is assembled into a twerp pump as shown in FIG. During rotation, 11 is the casing, 12.13 is the diaphragm installation push, 15 is the operating rod, 1f, 18 is the valve body on the suction side and discharge side, respectively, 20 is the pump drive eccentric plate, 21
is the fuel tank.

When the above-mentioned fuel bomb is assembled into a fuel circuit system and used, the diaphragm is required to have gasoline resistance, gasohol resistance, deterioration gasoline resistance, etc. on the gasoline contact side, and on the air contact side, Cold resistance, heat resistance, etc. are required. In addition, the required performance has become more stringent than ever before.

For this reason, it has been proposed to form the above-mentioned specific ACM compounded rubber layer (vulcanizate) on one or both sides of the base fabric, which can meet these requirements to some extent (JP-A-6
2-53353), the thickness of this PR compound rubber layer is usually 0.1 to 1■■.

(11: Here, the specified ACM is a mixture of acrylic rubber (polymer) and vinylidene fluoride resin in a weight ratio of 9515
~40/60 mixed polymer blend.

And, for the above acrylic rubber, ■Acrylic acid alkyl esters, acrylic acid alkoxy! One or more compounds selected from either or both of the substituted alkyl esters: 30 to 99.9%, ■Crosslinkable comonomer: 0.1 to 10%, and ■The above ■
5■ Other ethylenically unsaturated compounds copolymerizable with 20~
A multicomponent copolymer having a composition of 70% is included.

In addition, vinylidene fluoride resin has an average polymerization degree of too-
Includes xoooooo.

This specific ACM (raw rubber) usually contains various auxiliary materials, such as inorganic fillers such as carbon black, silica, and metal oxides, organic fillers such as lignin, and softeners and plasticizers. , an antioxidant, a yellowish coloring agent, etc., and furthermore, vulcanizing agents such as sulfur, peroxide, amine, polyvalent metal salt, etc. are appropriately added, kneaded, and used as a kneaded dough.

(2) The base fabric 1 is usually made of plain weave or twill weave using synthetic or natural fibers such as polyamide (nylon, aramid), polyester, cotton, etc. in view of the heat resistance and strength required for the diaphragm. use.

<Am to be solved by the invention> However, the vulcanized rubber layer made of the above-mentioned specific ACM compounded rubber did not have sufficient cold resistance, especially on the air contact side.

In view of the above, an object of the present invention is to provide a diaphragm that can have sufficient resistance to deterioration of gasoline on the gasoline contact side and sufficient cold resistance on the air contact side.

<Means for Solving the Problems> In order to solve the above problems, the inventors of the present invention have made extensive efforts in development and have come up with a diaphragm having the following configuration.

Vinylidene fluoride tree WiI/acrylic rubber (weight ratio)
A rubber layer is formed of a rubber vulcanizate of a blend polymer of San 10/90 to 30/70, and the acrylic rubber is made of ■acrylic acid alkoxy-substituted alkyl ester (ACAS), ■acrylonitrile (AN
), ■ A multi-component copolymer having a polymer composition of 1 cross-linkable 1 ■ acrylic acid alkyl ester (ACA"),
In use, in a diaphragm whose one side is a gasoline contact side and the other side is an air contact side, the polymerization composition of the acrylic rubber in the rubber vulcanizate of each rubber layer on the gasoline contact side and the air contact side is as follows: A diaphragm characterized by satisfying each of the following requirements.

former + total amount of ACAS and AN 24-88wt%ACA
S/AN (weight ratio) = 1 to 7, latter: ACAS and AN
(7) Total amount 34-80 wt% ACAS/AN (weight ratio) = a ~ 20゜〈F! The following five diaphragms of the present invention will be explained based on the mouth side. In addition, in the following description, the compounding unit is a weight unit unless otherwise specified.

A, ′! As shown in Figure J1, both surfaces of the base fabric 1 are provided with compounded rubber vulcanized layers 3 and 5. Both vulcanized rubber layers 3 and 5 have in common that they are made of a specific ACM compounded rubber layer having the following polymerization composition.

(1) The polymer is a blend polymer of vinylidene fluoride resin/acrylic rubber (weight ratio) IQ/90 to 30/70. If the amount of vinylidene fluoride resin is too small, it will be difficult to obtain gasohol resistance and resistance to deteriorated gasoline, and if it is in excess, processability and flexibility will deteriorate and the cost will increase, which is not desirable.

■Acrylic rubbers include ■acrylic acid alkoxy-substituted alkyl ester (ACAS), ■acrylonitrile (AN
), OC crosslinking monomer, and (2) acrylic acid alkyl ester (ACA) as polymerization components. Specific examples of each of the above polymerization components include JP-A No. 62-5335
Those exemplified in Publication No. 2 can be used.

(2) In the above, the polymerization composition of the acrylic rubber in the rubber vulcanizate of each vulcanized rubber layer on the gasoline contact side and the air contact side satisfies the following requirements, respectively.

■Gasoline contact side: Total amount of ACAS and AN 24-88
%, ^CAS/^N-1~7, where ACAS and AN
If the total amount is less than 24%, it tends to have an adverse effect on gasoline resistance, gasohol resistance, deteriorated gasoline resistance, and deteriorated gasohol resistance, and when it exceeds 88%, it tends to have an adverse effect on cold resistance and heat resistance. .

Further, when ACAS/AN is less than 1, problems tend to occur in cold resistance and heat resistance, and when it exceeds 7, gasoline resistance, gasohol resistance, deterioration gasoline resistance, and deterioration gasohol resistance are likely to be adversely affected.

■Air contact side: Total amount of ACAS and AN 34-80wt
%, ACAS/AN=8~20°Here, ACAS and A
If the total amount with N is less than 34%, it will have a negative effect on gasoline resistance, gasohol resistance, deteriorated gasoline resistance, and deteriorated gasohol resistance, and if it exceeds 80%, it will have a negative effect on cold resistance and heat resistance. Cheap.

Further, if ACAS/AN is less than 8, it is difficult to obtain sufficient cold resistance, and if it exceeds 20, the gasoline resistance, gasohol resistance, deteriorated gasoline resistance, and deteriorated gasohol resistance are likely to be adversely affected.

(3) The base fabric 1 is usually treated with an adhesive. The adhesive is preferably a composite adhesive in which an isocyanate adhesive is added to epoxy group-introduced nitrile rubber (hereinafter referred to as epoxidized NBR). Here, examples of the isocyanate adhesive include "Chemlock 402" commercially available from Lord Company. The amount of this isocyanate adhesive added is epoxidized NBR1
00 copies, 20 to 300 copies. If the amount is less than 20 parts, no improvement in adhesion can be expected, and if it exceeds 300 parts, the adhesion will deteriorate.

The adhesive can be applied to the base fabric by spraying, dipping roll,
A brush or the like is not particularly limited and may be used arbitrarily.

89 Next, a method for manufacturing the diaphragm of the present invention will be explained.

A kneaded dough of the FR rubber compound is coated (topping or extruded) on both sides of the base fabric 1 treated with the adhesive using a calender roll, an extruder, etc. to form a rubber layer 3.5.
form.

At this time, the compounded rubber for the rubber layer 3.5 is one in which the polymerization composition of the acrylic rubber for the contact side and the air contact side satisfies the above requirements.

The unvulcanized laminated sheet thus formed is subjected to vulcanization (press vulcanization, hot air vulcanization, etc.) and punching in an appropriate order to obtain the diaphragm of the present invention.

<Operations and Effects of the Invention> As described above, in the diaphragm of the present invention, each of the rubber layers on the gasoline contact side and air contact side is formed of a rubber vulcanizate of FR rubber having a specific polymerization composition of acrylic rubber. By doing so, it is possible to obtain a diaphragm that has sufficient deterioration gasoline resistance on the gasoline contact side and sufficient cold resistance on the air contact side.

Test Examples> Test examples conducted in order to confirm the effects of the present invention will be described below.

(1) Test Example 1: In the basic formulation shown in Table 1, in the specific ACM-based polymer of vinylidene fluoride resin/acrylic rubber = 17783, the polymerization composition of the acrylic rubber was as shown in Table 2. Physical property tests were conducted on each rubber vulcanizate obtained by vulcanization molding (press vulcanization = 165°C x 30 m1n) from the rubber compound based on JIS K6301.

The results of the physical property test are shown in Table 2. From the results of Table 'M2,
Rubber compounds for the gasoline contact side have excellent gasoline resistance, while rubber compounds for the air contact side have excellent cold resistance, and both open compounds have sufficient physical properties to withstand practical use. (2) Test Example 2: Base fabric (made of nylon 6, plain weave,
0.4 mmt), each side was topped with an FR rubber compound having a polymerization composition of acrylic rubber of 2nd surface motion 1/6 so that the rubber layer was 0.4 mmt, thereby forming an unvulcanized rubber laminate sheet. I got it.

Next, each unvulcanized laminated sheet was punched out to a size of 75 mmφ, 176°C x 10 m1n x 65 kg.
f/cm" condition, after vulcanization, in a constant temperature bath! 50
Secondary vulcanization was carried out under the conditions of 2 hours at .degree. C. to prepare four diaphragms having the combinations shown in Table N4.

Then, each diaphragm was assembled into a Tsuyuel pump as shown in FIG. 2, and a deterioration gasoline resistance test and a cold resistance durability test were conducted separately under the conditions shown in Table 4.

In addition, in the deterioration gasoline resistance test, a φ2 nozzle was installed in the middle of the OUT line, and a resistance was applied to the OUT line so that fuel gas also flowed to the return circuit, allowing the test to be performed under operating conditions similar to those of the actual vehicle. I did it. In addition, in the cold resistance test, the φ2 nozzle was not installed,
Tests were conducted under conditions that were more severe than the operating conditions of the actual vehicle.

The results are shown in Table 4. It can be seen that the diaphragm of the example of the present invention has sufficient resistance to deterioration of gasoline and cold resistance. Furthermore, it can be seen that the diaphragm of the comparative example cannot exhibit these effects.

Table 1 ACM rubber Synthesis polymer 100 parts Stearic acid 1 part Carbon black (
HAF) 40 parts fatty acid metal salt
1 part polyester binder l
O part Phosphate plasticizer 10 parts Vulcanizing agent 3.5 parts Table 2 Acrylic rubber polymerization composition unit Double part <abbreviation> ACAS Niacrylic acid alkoxy-substituted ester AN: Acrylonitrile ACA Niacrylic acid alkyl ester *Ethylene containing epoxy group Table of unsaturated compounds Rubber

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an example of a diaphragm to which the present invention can be applied, and Fig. 'fS2 is a cross-sectional view showing an example of a twine pump suitable for installing the diaphragm of the present invention. 1... Base fabric; 3...・Specific ACM compound rubber layer (gasoline contact side) 5・
...Specified ACM compound rubber layer (air contact side) Patent application: Toyoda Gosei Co., Ltd. Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] Vinylidene fluoride resin/acrylic rubber (weight ratio) = 1
A rubber layer is formed of a rubber vulcanizate of a blend polymer of 0/90 to 30/70, and the acrylic rubber is (a) acrylic acid alkoxy-substituted alkyl ester (ACAS), (b) acrylonitrile (AN), ( It is a multicomponent copolymer having a polymerization composition of c) a crosslinkable monomer and (d) an acrylic acid alkyl ester (ACA), and when used, it is used in a diaphragm in which one side is in contact with gasoline and the other side is in contact with air. A diaphragm, wherein the polymerization composition of the acrylic rubber in the rubber vulcanizate of each rubber layer on the gasoline contact side and the air contact side satisfies each of the following requirements. Former: total amount of ACAS and AN 24-88wt%, AC
AS/AN (weight ratio) = 1 to 7, latter: total amount of ACAS and AN 34 to 80 wt%, AC
AS/AN (weight ratio) = 8-20.