JPS58118372A - Diaphragm - Google Patents

Abstract

PURPOSE:To obtain an oil-resistant diaphragm excellent in the characteristics of deterioration resistance to gasoline, crack growth resistance, freezing resistance and the like, by forming the fluid contact surface side of the diaphragm with the use of rubber composition of hydrogenated NBR mixed with liquid NBR. CONSTITUTION:Less than 500 of number average molecular weight of liquid copolymer of unsaturated nitrile-conjugated diene group (liquid NBR) which is added in partially hydrogenated unsaturated nitril-conjugated diene (hydrogenated NBR), is easily extracted in a solvent so that a necessary crack growth resistance may not obtained, and more than 10,000 thereof gives no effect to the enhancement of crack growth resistance. Less than 2wt% additive amount of liquid NBR with respect to hydrogenated NBR does not exhibit the effect of the addition of liquid NBR. The upper limit should be less than about 50wt% at which the viscosity of the rubber composition lowers so that a bad influence such as, for example, permanent compression strain, affects the physical property of the material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil-resistant diaphragm that exhibits excellent properties such as anti-deterioration gasoline properties, crack growth resistance, and cold resistance on the liquid contact surface side, and in particular, to a It is effective when used in equipment such as μ pumps.

Modern fuel circuit systems, especially those equipped with electronic fuel injection systems,
Diaphragms used in FFI power circuit equipment are required to be resistant to deterioration of gasoline, as they are susceptible to deterioration due to the rise in temperature and internal pressure of gasoline that comes into contact with the diaphragm. Also,
Diaplum g! Since the liquid contact surface side is always in contact with gasoline, crack growth resistance against gasoline is required. Furthermore, as automobiles become more popular in extremely cold regions, a high degree of cold resistance is also required.

An object of the present invention is to provide an oil-resistant diaphragm having excellent properties such as resistance to deteriorated gasoline, crack growth resistance, and cold resistance, at least on the liquid contact surface side.

The diaphragm of the present invention is made of a gofu composition in which a liquid unsaturated nitrile-conjugated diene copolymer is added and mixed with a partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which the conjugated diene unit portion is hydrogenated. The above object is achieved by forming the liquid contact surface side with a 7Xl material or a material made of a rubber composition in which a wood-based vinyl resin is further mixed with the rubber composition.

Hereinafter, the diaphragm of the present invention will be explained based on illustrated examples.

Both sides of the diaphragm (@/diaphragm 2m in the diagram) and F
'One side of the i-liquid contact surface (diaphragm 2B in Figure 1)
is a liquid unsaturated nitrile-conjugated diene copolymer (hereinafter referred to as " Liquid NBILJ) was added and mixed, or vinyl chloride thread resin (hereinafter referred to as 1'-
Referred to as P V OJ) f: It is formed from a vulcanized product of a rubber composition added and mixed.

The above-mentioned H-added NBR is obtained by hydrogenating at least 50% of the conjugated diene unit portion of an unsaturated nitrile-conjugated diene copolymer rubber produced by emulsion polymerization or solution polymerization using a conventional method.

The above copolymer rubber to be hydrogenated is acrylonitri/L/
Unsaturated nitrides such as crylonitrile and/
, 3-1 tadiene, isoprene, /.

Copolymerized with at least seven types of conjugated dienes such as 3-pentadiene, or a part of the conjugated diene is copolymerized with acrylic acid, methacrylic acid, fuma/l'#, methyl ester such as itaconic acid, guchika ester, - Monoethylhex S//
It is a product obtained by copolymerizing an unsaturated carboxylic acid ester such as I/ester, or one substituted with N-methylolacrylamide or the like with the above unsaturated nitrile. Specifically, acrylonitrile μm butadiene copolymer rubber, acrylonitrile-isoprene copolymer rubber, acrylonitrile-butane-isoprene copolymer rubber, acrylonitrile-butadiene-methyl acrylate copolymer rubber, acrylonitrile μm butadiene-butyl acrylate copolymer rubber, For example, acrylonitrium getadiene copolymer (NBR) is most suitable.

The amount of bonded unsaturated diF in the Nil oxide added above is usually 10 to 70 vt%, and is appropriately determined within the above range depending on the compatibility with the PvC to be mixed and the intended use (application).

Furthermore, if the degree of hydrogenation of the conjugated diene unit is less than j0%, the physical properties targeted by the present invention cannot be obtained.The upper limit of the degree of hydrogenation may be 100%, but in the case of sulfur-based vulcanization, Due to the relationship with the sulfur rate, the degree of hydrogenation should be 2 g% or less.

In order to effectively obtain the compatibility with the liquid NBR #i and the H-added NB-o and the various physical properties aimed at by the present invention,
Unsaturated nitric μ10-70vt%, preferably Id20-
! Owt%, conjugated Nx o~lQwt%, preferably 2j~rijvt%, O-co□vt% of the bee yarn monomer copolymerizable with unsaturated nitrile and conjugated diene, preferably 0. /~/jvt%. The unsaturated nitrides and conjugated dienes are as described in the section of H-added NBR. Acrylonitrile is particularly preferred as the unsaturated nitrium, and butadiene and imprene are particularly preferred as the conjugated dienes. Examples of μ-based monomers include unsaturated acids such as acrylic acid, methacrylic acid, and itaconic acid;
Examples include vinylpyridine monomers such as pyridine and N-methylolacrylamide, but acrylic acid and methacrylic acid are particularly preferred.

If the number average molecular cap of the liquid NBR is less than 5oo-7, it will be easily extracted by the solvent and the required crack growth resistance will not be obtained.
If it exceeds 000, there is no effect of improving crack growth resistance, preferably 1000 to j000. Next, liquid N
The amount of BR added to the hydrogenated NBR is -vt % or more (inner multiplication).

If the content is 2vt%, there is no effect of adding liquid NBA, and the upper limit is about 3Qvt% (inner multiplier) where the viscosity of the rubber composition decreases and has an adverse effect on physical properties such as compression set.

The above-mentioned PvC is made by co-electrifying monoolefin yarns such as polyvinyl chloride or seeded vinyl acetate, and adding PvC to the rubber composition of H-added NBIL and liquid NBR. atyojut% or more (inner hook), preferably KoO! It is around t%. The effect of adding PvCIm is not observed when the amount of rvC is increased, and the upper limit is naturally determined as the resin-like properties become stronger as the amount of rvC increases, and there is a limit at which the rubber-like properties are impaired even if vulcanization is possible. Therefore P
The amount of VC added may be appropriately determined within this range depending on the purpose of use and required performance.

H-added N B R, liquid N B R, saG: bLlit
P V Of: There are no particular restrictions on the mixing method, but
Methods such as kneading using a low μ or Banbury mixer, or dispersing and mixing in a liquid to co-precipitate and then drying.
take.

In the rubber composition of the above-mentioned H-added NBR and liquid NBR, or in each raw material rubber to which FVC is added to this composition, examples of various auxiliary materials normally used include car pump hooks, V-rica, metal oxides, etc. Inorganic fillers, organic fillers such as lignin, softeners, plasticizers, antioxidants, colorants, etc. are appropriately blended, and sulfur-based or peroxide-based vulcanizing agents are added as appropriate and kneaded. do. This rubber material was calendered using nylon pi1. ! Im, Bo')"-sf#M1.ljk, made of cotton fat, topping is performed with nine base cloth, and then a diaphragm is manufactured by press-molding a book punched into a predetermined shape and size. 5 conditions are mold temperature/jO~/riO'C1 ecstasy time 3~
30 win, molding pressure s O ~ / s o kg'
/CI! It is. At this time, the topping layer that is not on the liquid contact surface side does not need to be made of the above-mentioned H#5IXJNBR rubber, and other NB rubber, OR, OHR, etc. can be used.

As shown in the examples below, the diaphragm manufactured in this way has particularly good resistance to crack growth and resistance to deterioration of gasoline, compared to the case where the inner layer is formed from a conventional vulcanizate of Nl3B or its PVC mixed rubber. Excellent in quality, n1iJ Q quality,
Furthermore, the normal physical properties are 9%, showing well-balanced properties.

Examples will be described below along with comparative examples to demonstrate the effects of the present invention.

! *Each test piece for Examples and Comparative Examples was made by rendering the thickness of a cod using a rubber material with the formulation shown in Table IJg1, and then punching it out to a size of 7jff)Illφ/70 A diaphragm (without base fabric) was manufactured by press molding under the conditions of °C x 11m1n and 100kg'/j. Test pieces were punched out from this diaphragm and various physical property tests were performed using the following methods.
It is listed in the table.

Measured by normal state physical properties JIBK-430/9 (test piece; Danpe μ
Type No. 3).

(70”Q J containing ivt% of deterioration-resistant gasoline fluorocarbon oxide)
I 87 Yux IW C@liquid C tank/l/type JX
Continue immersing the No. B3 test piece while renewing the liquid every 21X hours (/cycle). After each cycle of each display, take out the test piece, leave it for 1 hour, and then place it under reduced pressure for 6 hours.
The physical properties of the test piece dried at 0°C were determined by JI8 -4-?
It was measured according to O/.

(0 Crack Growth Resistance Dampe μ type JXB No. 1 test piece is marked with a -n width crack with a marking line of 0M spacing, and the test piece is s
An elongation of 0% (between marked lines≦□gl) was given, and the test piece given this elongation was immersed in llo''CJI8 Fuyue A/D, and the time until the test piece broke was measured.

■ Heat aging resistance / Physical properties of a test piece of Danbe μ type No. 3 heat aged under the conditions of -0 x 70 o x 70 hours r hours) were measured before and after heat aging in accordance with JZ8 1≦3゜l, The differences in breaking strength change rate, breaking elongation change rate, and hardness with respect to normal physical properties were expressed as ΔTB, ΔKB, and ΔH8, respectively.

(E) Cold resistance Impact embrittlement temperature was measured according to JIBK-430/&:.

(F) Gasoline resistance 20X, 1OX21111tf) 410”cJ on test piece
It was immersed in IB-y UNIL&/C for 41 hours, the volume before and after immersion was measured, and the rate of change was shown.

(G) Gasohol resistance CoQX CoOX, 2 mflllt test piece was immersed in aOCC41 containing methano-A/CoQ vo1% for a time, and the volume before and after immersion was measured. , the rate of change was displayed.

From the results in Table 1, it can be seen that the guyah hum of the present invention is (Example/
It can be seen that samples 1 to 2) have excellent resistance to deteriorated gasoline, crack growth resistance, and cold resistance, and also have good normal physical properties, heat resistance, etc., and have a well-balanced physical property. Regarding crack growth resistance, compared to HjIltxJNB (comparative example/), liquid N11111 was added (Example/Kohakana), and if rye is added and mixed, R-added Nl1B has a liquid state. It can be seen that the crack growth resistance is further improved compared to the case where NBILf is mixed.

[Brief explanation of drawings]

Figures 1g7 to 1g2 are cross-sectional views showing an example of a diamond 7 hum to which the present invention is applied. 1...Base fabric, 21% 2B...Diamond cloth, L...
・Liquid contact surface l1111 Patent application: Toyoda Gosei Co., Ltd.) Eta Jidosha Kogyo Co., Ltd. Japan Zeon Co., Ltd. Figure 2 Voluntary amendment To the Commissioner of the Patent Office (To the Examiner of the Patent Office) 1, =
The size of Ji matters 1932 Patent application No. 2/32
7S No. 2, Name of the invention Diaphragm 3, Person making the amendment Relationship to the matter Patent application Person: Month, Day, Showa (Date of shipment: Showa
Date) 6. Number of inventions increased by amendment 7, Supplement 1]・° Subject 8, Sleeve 11・ Contents of: (1) #Amend the scope of claims as per paper M. (2) "Liquid contact surface" in lines 1-15 to 16 of page 2 and line 5 of page 3 of the specification are corrected to "L3 contact surface" respectively. (3) Correct "liquid contact surface" on page 2, line 10 and page 3, line 10 to read "r liquid path and u contact surface." (4) On page 8, line 18, replace "indicates characteristics" with the following sentence. 2. Claims (1) Partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which at least 50% of the conjugated diene units are hydrogenated has a number average molecular weight. 500 to 10,000 liquid unsaturated nitrile-conjugated diene copolymer is 2 wt% or more (inside)
A diaphragm whose zero contact surface side is formed of a vulcanized product of the added rubber composition. (2) A liquid unsaturated nitrile-conjugated diene copolymer having a number average molecular weight of 500 to 10,000 is added to a partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which at least 50% of the conjugated diene units are converted to water. A diamond characterized in that the 0 contact surface side is formed of a vulcanized product of a rubber composition in which 2 wt% or more (inner layer) of polyvinyl chloride resin and 5 wt% or more (inner layer) of vinyl chloride resin are added and mixed. plum.

Claims (1)

[Claims] (1) 2wt of a liquid unsaturated nitrile-conjugated diene copolymer having a number average molecular weight of joo to 10,000 is added to a partially hydrogenated unsaturated nitrile-conjugated diene thread copolymer rubber in which at least 50% of the conjugated diene units are hydrogenated. A diaphragm characterized in that the liquid contact surface side is formed of a vulcanized product of a rubber composition to which 9% or more (inside) is added. , (2) Partially hydrogenated unsaturated in which at least 50% of the conjugated diene units are hydrogenated; a liquid unsaturated nitrile-conjugated diene copolymer having a number average molecular weight of jOo to 10,000 is added to the tri-conjugated diene copolymer rubber. % or more (inner hook), and cyclized vinyl to thread resin is more than j wt % (
#I) A diaphragm characterized in that the liquid contact surface side is formed of a vulcanized product of a rubber composition added and mixed.