Curable resin composition, method for producing curable resin composition, and method for measuring surface tackiness of viscoelastic material
Provided is a curable resin composition which can be cured to form a material (cured product) that has low tack properties and resists adhesion of garbage. The present invention provides a curable resin composition comprising polysiloxane (A) having not less than 2 alkenyl groups in the molecule and polysiloxane (B) having not less than 2 hydrosilyl groups in the molecule, wherein (T+Q)/D>0.3 and M+D+T+Q=1 are satisfied regarding all silicon atoms contained therein, the amount of the hydrosilyl groups with respect to 1 mol of aliphatic carbon-carbon double bonds present therein is 0.9 to 5.0 mol, and a cured product of the curable resin composition exhibits a separation strength of not more than 0.40 N per mm 2 in separation load evaluation and/or a total separation load of not more than 0.018 N·mm per mm 2 .
1. A method for measuring the surface tackiness of a viscoelastic material, comprising:
step A of contacting an object and the viscoelastic material with each other so as to attain a contact area of not less than 50 mm 2 , applying a load thereto, and subsequently relaxing the stress;
step B of separating the object and the viscoelastic material by the application of displacement in the direction of separation; and
step C of recording change in stress on the contact face from the contact to the separation, obtaining a curve of displacement on the x-axis and stress on the y-axis, and quantifying tackiness from the obtained curve,
wherein the face of the object to be contacted with the viscoelastic material is a plane, and the plane area of the object is larger than the area of the contact portion between the viscoelastic material and the object.
2. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein the step A involves using a stress detection mechanism having a mount and the object, placing a flat-shaped viscoelastic material onto the mount, continuously applying a load by pressing the object against the viscoelastic material such that the contact face between the viscoelastic material and the object is a plane, and subsequently relaxing the stress.
3. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein in the step C, a maximum stress value in the curve is obtained as the tackiness value of the viscoelastic material.
4. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein in the step A, a value determined by dividing the load applied after the contact of the object and the viscoelastic material by the contact area is 0.1 to 4 MPa.
5. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein in the step A, the time for which the load is applied after the contact of the object and the viscoelastic material is 0.5 to 10 minutes.
6. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein in the step B, the rate at which the object and the viscoelastic material are separated is set to a rate of 5 mm/min, 10 mm/min, 20 mm/min, 30 mm/min, 50 mm/min, 70 mm/min, 100 mm/min, 150 mm/min, 300 mm/min, or 500 mm/min.
7. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein the thickness of the viscoelastic material is 0.5 to 5 mm.
8. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein the method is carried out in an environment involving a temperature of 10 to 30° C. and a humidity of 30 to 70% RH.
9. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein in the step A, the load is applied from the object side or the viscoelastic material side.
10. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein in the step A, at least one of the object and the viscoelastic material is moved in the direction of contact, the direction of contact and the direction of load application are a vertical direction, and the direction of contact is vertically upward or vertically downward.
11. The method for measuring the surface tackiness of a viscoelastic material according to claim 1 , wherein the direction of movement for the contact in the step A is opposite to the direction of movement for the separation in the step B.