JPS62232497A - Sliding material - Google Patents

Abstract

PURPOSE:To obtain a sliding material having excellent lubricity, wear resistance, and water resistance, by providing a coating of a particular fluorinated polyether polymer on the surface of a urethane rubber elastomer. CONSTITUTION:A crosslinking agent (e.g., 1,4-butanediol) is added to a prepolymer comprising polyols, such as polyester polyol or polyether polyol, followed by crosslinking, thereby obtaining a urethane rubber elastomer. A part or the whole of the surface of the urethane rubber elastomer is coated with an org. solvent (e.g., acetone) solution contg. 0.3-10.0wt% fluorinated polyether polymer of formulae I and II having units contg. a polar group reactive with or exhibiting affinity for the urethane rubber elastomer, followed by drying to form a coating. The coating is rubbed with a soft cloth or paper to give a gloss and, at the same time, to remove excess fluorinated polyether polymer.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to sliding materials.

[Conventional technology]

Urethane-based rubber-like elastic bodies include styrene-butadiene rubber (SBR) and acrylonitrile-butadiene rubber (NB
R), imprenebohm (IR), chloroprene rubber (
Compared to synthetic rubber materials such as CR), butadiene rubber (BR), and acrylic rubber, it has superior lubricity and wear resistance (particularly tear resistance), so it is used, for example, in paper feed rollers for office equipment and food processing equipment. Although they are widely used in kneading rollers, automobile safety pads or glass runs, various valves, oil seals, etc., their sliding characteristics are not satisfactory, and they require large ψ driving force.
It makes a friction noise and causes stick-slip. Shirisu, Baka8ku, usage time is long. 6, the frictional resistance increases, the wear becomes severe, and furthermore, the heat generated in the sliding portion t increases, leading to deformation of the rubber-like elastic body itself. Furthermore, since the urethane rubber elastic body has poor water resistance, the conditions for its use (atmosphere, time, etc.) require considerable restrictions.

In general, in order to reduce the frictional resistance of a sliding material with rubber-like elasticity, it is necessary to attach a fluororesin film to the surface of the sliding material (for example, Japanese Patent Publication No. 46-23681), or ◎ film-forming polymer. Methods include applying and baking a liquid in which a solid lubricant such as a fluororesin is dispersed in an organic solvent, or baking a fluoroalkyl copolymer obtained by copolymerizing polyfluoroalkyl with other monomers. is taken.

However, each of these methods has the following drawbacks. In other words, in method (1), since the adhesion of the fluororesin film to the base material is very poor, it is necessary to perform surface treatment (by alkali metal or ion sputtering, etc.) in advance, and even if surface treatment has not been performed, However, the adhesion is insufficient and the film often peels off during use, and molded products with complex shapes cannot be used.
Methods ■ and ○ are superior to method ■ in terms of adhesive strength and the ability to lower the baking temperature, but they do not inherently have properties such as lubricity. Since polymers or monomers arranged randomly or in blocks through copolymerization are used, there is a drawback that sufficient lubricity is not exhibited.

[Problem that the invention seeks to solve]

As described above, there has been a problem in that none of the urethane-based rubber-like elastic bodies produced by conventional techniques are satisfactory in terms of lubricity, abrasion resistance, and water resistance.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a coating made of a fluorinated polyether polymer having a unit containing a polar group that is reactive or has an affinity for a urethane-based rubber-like elastomer. This method employs a method of providing a part or all of the surface of the shaped elastic body, and the details of this method will be described below.

First, the urethane rubber-like elastic body of the present invention is a rubber-like elastic body obtained by reacting polyester polyol, polyether polyol, or other polyols with incyanate. Polyester polyols include polybasic acids (such as adipic acid, succinic acid, sebacic acid, phthalic acid, and other aliphatic or aromatic dicarboxylic acids) and polyhydric alcohol polymers (such as polyethylene glycol, polydiethylene glycol,
Examples include polyester polyols that are reaction products with polypropylene glycol, polydipropylene glycol, polybutylene glycol, other diol polymers, triol polymers, etc., and ring-opening polymers of cyclic esters. The molecular weight of the above-mentioned polyhydric alcohol polymer is not particularly limited, but since it is a suitable rubber-like elastic body, a molecular weight of about 1,000 to 3,000 is suitable. Polyether polyols are obtained by ring-opening polymerization of epoxides or tetrahydrofuran, and polyether polyols obtained by adding epoxides to compounds having at least two hydrogen atoms to which these cyclic ethers can be added are suitable. be. This epoxide is, for example, ethylene oxide, propylene oxide,
butylene oxide, etc. Compounds that provide hydrogen atoms that can be added to cyclic ethers include, for example, the above-mentioned polyhydric alcohol polymers, polyphenols, polyamides, polyamines, etc. Among them, polyhydric alcohol polymers, i.e., especially those with limited molecular weight, are Although it is not limited, polyethylene glycol (molecular weight of about 1000 to 6000), polypropylene glycol (molecular weight of about 1000 to 2000), polytetramethylene glycol, etc. are preferable. Other polyols include, for example, polybutadiene glycols made of butadiene homopolymers or copolymers with acrylonitrile or styrene, polyester polyols, polycarbonate polyols, and the like. Furthermore, inocyanate needs to be a polyisocyanate with two or more aliphatic or aromatic functional groups, but the more functional groups there are, the more likely it is to crosslink and lose rubber elasticity, so for example, hexamethylene-1, 6-diisocyanate, toluene-2,4-
Diisocyanate, metaphenylene diisocyanate,
Diisocyanates such as naphthalene-1,5-diisocyanate and diphenylmethane-4°4'-diisocyanate are preferred.

Such a urethane-based rubber-like elastic body is produced by making a prepolymer consisting of various polyols and isocyanates, and then adding a crosslinking agent such as 1,4-butanediol, methylenebisdichloroaniline, trimethylolpropane, or triisopropanolamine to this prepolymer. In addition, it may be cross-linked, and it may also be a urethane-based thermal block copolymer consisting of a combination of three components: trifunctional polyol constituting the soft segment, short chain glycol and diincyanate constituting the nodal segment. Even if a plastic elastomer is used, this invention will not be hindered in any way.

Next, the polar group showing reactivity or affinity with the urethane rubber-like elastic material of the present invention is, for example, -N
GOl-OH, -COOH, -NHRl (herein R1), the fluorinated polyether polymer having units containing such polar groups is -CxF2x-〇-(herein, X is 1 to
Average molecular weight of approximately 1000 with main structural unit being (an integer of 4)
~10,000, the perfluoropolyether group improves lubricity and wear resistance, and the polar group improves the adhesion between the fluorinated polyether polymer coating and the urethane rubber-like elastic body. This is useful. As mentioned above, the urethane-based rubber-like elastic body of the present invention is formed based on urethane bonds formed by the reaction between incyanate and active hydrogen groups, but other than these bonds, urea bonds, billet bonds, etc. , allophanate linkage etc. can also be included in the side chain or end -NGO1-OH5-NH2fl
Since there are many cases where any functional group remains, among the polar groups mentioned above, the active hydrogen possessed by urethane bonds, urea bonds, etc.
OH group or -NH2 group versus chain or terminal -
-OH, -NHR,, - reactive towards NCO groups
COOH, -5H, etc. are preferred, and those in which these groups are located at both terminals of the fluorinated polyether polymer are most effective, and particularly preferred. In addition, if a fluorinated polyether polymer having units containing -NGO and a fluorinated polyether polymer having units containing -OH are used together, the wear resistance is further improved. It is also possible to use together different types of fluorinated poly-ether polymers having units containing. Specific examples of the above-mentioned fluorinated polyether polymers are as follows.
It goes without saying that there is no problem in using these alone or in combination. That is, HOOC-CF20(-C2
F40 輻云CF20h CF2COOH1 horse CCXX
E-CF20+C2F40dCF20q CF2C00
CJ (3, HCH3-CF20 (-C2F40 Yagura Po CF
2O Sushi 12 (1), etc., and furthermore, a method in which a fluorinated polyether polymer whose polar group is a hydroxyl group and an incyanate that does not contain various polyfluoropolyether groups, or a method where the polar group is an incyanate A method may be adopted in which a fluorinated polyether polymer as a group is used in combination with various diamines, triamines, diols, triols, etc. that do not have polyfluoropolyether groups.

The fluorinated polyether polymer of this invention may not be used with urethane-based rubber-like elastic bodies or fluorinated polyether polymers as long as it does not adversely affect its properties such as lubricity, abrasion resistance, and adhesion to substrates. Organopolysiloxanes or polyfluoroalkyl polymers having reactive polar groups may be added as appropriate, but in order to maintain very good wear resistance, fluorinated polyether polymers are the main structural unit. It is desirable that

To form such a fluorinated polyether polymer film, organic solvents (for example, acetone, ketones such as methyl ethyl ketone, esters such as methyl acetate, ethyl acetate, isomeamyl acetate, diethyl ether, dioxane, etc.) are generally used. Ethers such as methyl chloroform, trichloroethylene, tetrachloroethylene, tetrachlorodifluoroethane, 1,1.2-) 1)
Chloro-1,2゜2-trifluoroethane [Freon 1
A coating liquid obtained by dissolving or dispersing a fluorinated polyether polymer to an appropriate viscosity in one or a mixture of two or more halogenated hydrocarbons such as 131 is sprayed onto the urethane rubber-like elastic body. Alternatively, the elastic body may be immersed in the coating solution, but the immersion method is preferable from the viewpoint of reducing the consumption amount of the coating solution. Note that the concentration of the fluorinated polyether polymer in this coating liquid is not particularly limited;
In terms of cost (approximately 0.3 to 10.0% by weight, especially considering the characteristics of the thin film formed, 0.5 to 5.0% by weight)
It can be said that about % by weight is preferable. After coating)
After drying, the surface is polished with a soft cloth or paper to give it a gloss, but this operation simultaneously removes excess fluorinated polyether polymer. because,
If the coating is too thick, it will contain an excess of fluorinated polyether polymer, and as a result, it will have many free reactive groups that are not involved in adhesion to the urethane rubber-like elastic material, and the sliding material This is because this adversely affects essential lubricity and wear resistance. Although the main purpose of drying after coating film formation is to remove organic solvents, heating during drying may also be used to increase the reactivity between the polymer in the coating film and the substrate. Alternatively, heat treatment may be appropriately inserted after drying.

stomach.

〔Example〕

The raw materials used in the Examples and Comparative Examples are listed below. In order to simplify the substance names or structural formulas, the numbers 1 to [phase] added at the beginning of each raw material will be used, and all blending ratios will be expressed in weight %.

(1) Urethane-based rubber-like elastic body ■Polyester type urethane rubber (manufactured by Tigers Polymer Co., Ltd.; Tyburen TR100-7, hard 1 JISA scale 70), (2) Fluorinated polyether polymer (manufactured by Montefluos, Italy: Fuomblin Z- DISO
C1 average molecular weight approximately 2000), ■HOOC-CF20
fC2F40 Lucky dog CF2O 2CF2Cα aim (manufactured by the same company: Fomblin Z-DIACID, average molecular weight approximately 2000
'), ■Hα upper 2-CF20-fC2F40Fuku〆CF2O size C
F2 20H (manufactured by the same company: Fonburin Z-DOL, average molecular weight approximately 2000),
(Manufactured by the same company: Fomblin Z-25, average molecular weight approximately 160
00), (3) Organopolysiloxane ■Carboxyl group-containing polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.: Carboxyl-modified silicone oil X-22-370
1, E), (2) Hydroxyl group-containing polysiloxane (manufactured by the same company: Silicone Diol X-22-160C).

■Amine group-containing polysiloxane (Niamino-modified silicone oil
2H40t-1 [Phase] Copolymer of perfluoroalkyl and methyl methacrylate (manufactured by NOF Corporation: hydroxyl group-containing perfluoroalkyl copolymer, MODIPER F100), Examples 1 to 3: As a urethane-based rubbery elastic body, A test piece for a friction/wear test was prepared from the plate-shaped molded product of the raw material (1). On the other hand, as the fluorinated polyether polymer, raw materials (1), (2), (2) and (2) were used as shown in the table. Then, these fluorinated polyether polymers were added at a concentration of 2.0% F.
This was dissolved in Freon 113 to prepare a coating liquid for dipping the urethane rubber-like elastic material test piece. The test pieces dipped in this coating solution were dried and heat treated at 70°C for 1 hour, and then their lubricity, abrasion resistance, water repellency, etc. were measured.
This was offered to me. The lubricity and wear resistance were measured using a thrust type friction tester (manufactured in-house) at a load of 3 kg/cm.
2. Under the condition of a speed of 1 m/min, the bearing steel (SUJ 2
), and the lubricity was judged from the size of the friction coefficient, and the wear resistance was judged from the stability of the change in the friction coefficient over time. Further, water repellency was determined by determining the contact angle of the test piece against water E using a goniometer type contact angle tester manufactured by Elma Optical Co., Ltd. The results obtained are summarized in the table.

Comparative Examples 1 to 7: Instead of the fluorinated polyether polymer in Examples 1 to 3 above, different types of polymers ~ [phase] as shown in the table were coated (no polymer in Comparative Example 1). Example 1 except that
A test piece similar to 3 was prepared.

However, in Comparative Example 7, the copolymer [phase] was used at a concentration of 3%.
A coating liquid was prepared by dissolving a mixture of cyclohexanone and methyl isobutyl ketone (1:1) together with a curing agent (hexamethylene diisocyanate) and a catalyst (dibutyltin dilaurate). did. Note that the conditions for drying and heat treatment after immersion in this coating liquid I are exactly the same as in the examples. The results of measurements on each of the obtained test pieces are also listed in the table.

As is clear from the table, in Examples 1 to 3, the coefficient of friction is not only low, but also fluctuates little during the sliding period, and is stable and low even during long-term sliding. The values are maintained, and both exhibit excellent abrasion resistance. On the other hand, even though the friction coefficient in Comparative Example 1, in which no film was formed on the surface of the base material, was relatively low at the beginning of sliding, it sharply increased as the sliding time elapsed, and 12
Before 0 minutes had passed, the test piece generated enough heat to cause thermal deformation (the numbers in parentheses in the table are estimated values). In addition, Comparative Example 2 using a fluorinated polyether polymer (■) having no polar groups, Comparative Examples 3.4 and 5 (using polysiloxanes (■, ■, ■) containing reactive groups, and fluoroalkyl polymers containing no polyether) Although the friction coefficient in Comparative Example 6 using a polymer (containing a hydroxyl group as a polar group) was very low at the initial stage of sliding, it became higher as the sliding time progressed, and the fluoroalkyl The friction coefficient in Comparative Example 7 using polymer (10) was a high value from the beginning of sliding,
As the sliding time elapsed (it gradually increased due to fatigue), it can be said that the friction resistance and abrasion resistance of Comparative Examples 1 to 7 are all far inferior to Examples 1 to 3. As is clear from the table, the water repellency in Examples 1 to 3 is as follows:
This was superior to Comparative Example 1.

〔effect〕

As described above, the sliding material of the present invention has excellent sealing properties inherent to the urethane rubber-like elastic material, good followability against deformation,
In addition to properties such as vibration isolation, this elastic body has excellent friction resistance, abrasion resistance, and water resistance due to the lubricating thin film that is closely coated, making it possible to withstand long-term sliding. Its stability and reliability are extremely high, so it can be used for example in automobiles,
It can be widely used as parts in all fields such as office equipment, automatic control equipment, aviation/space equipment, medical equipment, other electrical/electronic equipment, and general industrial machinery and equipment. Among them, this material is suitable for paper feed rollers in copying machines, kneading rollers in the food industry, safety pads for automobiles, glass runs or wiper blades, various shock absorbers, various valves, oil seals, etc. It can be said that the significance of the invention is extremely large.

Claims (1)

[Claims] A coating made of a fluorinated polyether polymer having a unit containing a polar group that exhibits reactivity or affinity for the urethane-based rubber-like elastic material is provided on part or all of the surface of the urethane-based rubber-like elastic material. A sliding material characterized by: