Resol phenolic resin for friction material, method for producing the same, adhesive for friction material, and wet friction plate
According to the present invention, there is provided a resol phenolic resin for a friction material wherein the resol phenolic resin has a structural unit A represented by Formula (1) and a structural unit B represented by Formula (2): wherein in Formula (1), m represents an integer of 1 or more; in a case where m is 1, R represents a methylol group; and in a case where m is 2 or more, R's independently represent a hydrogen atom or a methylol group and at least one R is a methylol group; and wherein in Formula (2), n represents an integer of 1 or more; in a case where n is 1, R represents a methylol group; and in a case where n is 2 or more, R's independently represent a hydrogen atom or a methylol group and at least one R is a methylol group.
1. An adhesive for a friction material comprising:
a resol phenolic resin for a friction material; and
a polyvinyl butyral resin,
wherein resol phenolic resin for a friction material has a structural unit A which is modified by dimethylphenol and is represented by Formula (1) and a structural unit B which is represented by Formula (2);
wherein in Formula (1), m represents an integer of 1 or more; in a case where m is 1, R represents a methylol group; and in a case where m is 2 or more, R's independently represent a hydrogen atom or a methylol group and at least one R is a methylol group; and
wherein in Formula (2), n represents an integer of 1 or more; in a case where n is 1, R represents a methylol group; and in a case where n is 2 or more, R's independently represent a hydrogen atom or a methylol group and at least one R is a methylol group and
wherein when the ratio of the structural unit A with respect to all structural units having a phenolic hydroxyl group contained in the resol phenolic resin for a friction material is defined as a dimethylphenol modification rate, the dimethylphenol modification rate is greater than or equal to 13% and less than or equal to 50%.
2. The adhesive for a friction material according to claim 1 , further comprising resorcin.
3. The adhesive for a friction material according to claim 1 ,
wherein the dimethylphenol is 3,5-dimethylphenol.
4. The adhesive for a friction material according to claim 1 , further comprising an organic solvent.
5. The adhesive for a friction material according to claim 4 , wherein the organic solvent is one selected from the group consisting of methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, and glycerin.
6. The adhesive for a friction material according to claim 4 , wherein the organic solvent is toluene or xylene.
7. The adhesive for a friction material according to claim 4 , wherein the organic solvent is toluene.
8. A wet friction plate comprising:
a friction material;
a metal base material; and
an adhesive according to claim 6 interposed between the friction material and the metal base material.