Glass fiber structure designed to reinforce bonded abrasive articles

Abstract

The invention relates to a structure based on glass fiber coated with a resin composition designed to reinforce bonded abrasive articles, the resin composition including the following constituents in the proportions indicated, expressed in percentage by weight of solid matter: 75 to 98% of a mixture of at least one novolac having a glass transition temperature lower than or equal to 60 C. and at least one novolac having a glass transition temperature above 60 C., 0.5 to 10% of at least one wax, 0 to 3.5% of at least one plasticizing agent.

Claims

1. A resin composition, comprising the following, expressed in percentage by weight 25 to 55% of at least one first novolac having a glass transition temperature lower than or equal to 60 C., 10 to 30% of at least one second novolac having a glass transition temperature above 60 C., 0.5 to 6.5% of at least one wax, 0 to 2.5% of at least one plasticizing agent, 25 to 45% of at least one alcohol, 0 to 15% of water, wherein the resin composition does not comprise a crosslinking agent.

2. The resin composition of claim 1, wherein the alcohol is methanol, ethanol, isopropanol, or a mixture thereof.

3. The resin composition of claim 1, wherein the first novolac has a glass transition temperature above 40 C.

4. The resin composition of claim 1, wherein the second novolac has a glass transition temperature above or equal to 80 C.

5. The resin composition of claim 1, wherein the second novolac has a glass transition temperature below or equal to 100 C.

6. The resin composition of claim 1, wherein the first novolac and the second novolac are obtained by a process comprising reacting phenol and formaldehyde in a formaldehyde/phenol molar ratio that varies from 0.75 to 0.85.

7. The resin composition of claim 1, wherein the wax is at least one paraffin wax, at least one ethylenebisamide wax or a mixture thereof.

8. The resin composition of claim 1, wherein the wax content does not exceed 5% by weight of solid matter of the resin composition.

9. The resin composition of claim 1, wherein the wax content does not exceed 3% by weight of solid matter of the resin composition.

10. The resin composition of claim 1, wherein the plasticizing agent is alkylphosphate, phthalate, triethanolamine, oil, polyhydric alcohol or a mixture thereof.

11. The resin composition of claim 1, wherein the plasticizing agent content does not exceed 1% by weight of solid matter of the resin composition.

12. The resin composition of claim 1, wherein the wax is a paraffin wax, wherein the paraffin wax is polyethylene or polypropylene.

13. The resin composition of claim 1, wherein the wax is an ethylenebisamide wax, wherein the ethylenebisamide wax is N,N-ethylenebis (steramide).

Description

EXAMPLE 1

(1) A resin composition was prepared comprising the following constituents:

(2) TABLE-US-00001 (% by weight) (% solid matter) Novolac.sup.(1) (Tg around 40 C.) 50.0 76.47 Novolac.sup.(2) (Tg around 80 C.) 13.0 20.58 Polyethylene wax .sup.(3) 2.0 2.95 Water 3.0 Alcohol 32.0

(3) The resin composition had the following properties: flexibility: 35 adhesive power: 0 N at t=0 0.13 N at t+15 days 2.37 at t+30 days

EXAMPLE 2

(4) A resin composition was prepared comprising the following constituents:

(5) TABLE-US-00002 (% by weight) (% solid matter) Novolac.sup.(1) (Tg around 40 C.) 47.0 74.28 Novolac.sup.(2) (Tg around 80 C.) 13.0 20.00 Polyethylene wax .sup.(3) 3.5 5.72 Water 5.5 Alcohol 31.0

(6) The resin composition had the following properties: flexibility: 35 adhesive power: 0.80 N at t=0 1.20 N at t+15 days 1.35 at t+30 days

COMPARATIVE EXAMPLE 1

(7) A resin composition was prepared under the conditions of example 1, modified in that it only contained the novolac.sup.(1):

(8) TABLE-US-00003 (% by weight) (% solid matter) Novolac.sup.(1) (Tg around 40 C.) 65.0 100 Alcohol 35.0

(9) The resin composition had the following properties: flexibility: >30 adhesive power: 88.44 N at t=0

COMPARATIVE EXAMPLE 2

(10) A resin composition was prepared under the conditions of example 1, modified in that it comprised the following constituents:

(11) TABLE-US-00004 (% by weight) (% solid matter) Novolac.sup.(1) (Tg around 40 C.) 59.0 94.20 Polyethylene wax .sup.(3) 3.5 5.80 Water 5.5 Alcohol 32.0

(12) The resin composition had the following properties: flexibility: >30 adhesive power: 26.95 N at t=0

COMPARATIVE EXAMPLE 3

(13) A resin composition was prepared under the conditions of example 1, modified in that it comprised the following constituents:

(14) TABLE-US-00005 (% by weight) (% solid matter) Novolac.sup.(1) (Tg around 40 C.) 52.0 78.80 Novolac.sup.(2) (Tg around 80 C.) 14.0 21.20 Alcohol 34.0

(15) The resin composition had the following properties: flexibility: 35 adhesive power: 34.40 N at t=0

EXAMPLE 3

(16) This example illustrates the application of the resin composition in a semi-industrial installation.

(17) A glass fiber fabric (grammage): 198 g/m.sup.2; warp thread: EC 204 tex s/z; weft thread RO 408 tex), 0.5 m wide, unwound from a reel, was disposed on a coating line operating continuously. On its path, the fabric passed into an impregnating bath containing the resin composition and was then treated in an oven comprising a first section heated to 125 C., and a second section heated to 115 C., before being collected in the form of a reel.

(18) The resin composition comprised the following constituents:

(19) TABLE-US-00006 (% by weight) (% solid matter) Novolac.sup.(1) (Tg around 40 C.) 50.0 77.15 Novolac.sup.(2) (Tg around 80 C.) 14.0 20.77 Polyethylene wax .sup.(3) 1.3 2.08 Water 1.7 Alcohol 33.0 .sup.(1)Phenol-formaldehyde novolac: M.sub.n = 829; M.sub.w = 2176; ethanol solution at 65% by weight solid matter. .sup.(2)Phenol-formaldehyde novolac: M.sub.n = 1247; M.sub.w = 5779; solution with 70% by weight solid matter in a 25:5 ethanol:methanol mixture. .sup.(3) Marketed under the reference Hydrocer 69 by Shamrock.

(20) The reinforcing fabric had the following properties: Amount of dust: 0.03% Adhesive power: 0 N Tensile strength (warp thread): 304 N Tensile strength (weft thread): 343 N Loss on ignition: 30% Volatile compounds content: 4.65%