Aqueous binder composition for fibres and fibrous products produced

Abstract

An aqueous inorganic or hybrid binder composition includes (as % by weight of the solid matter): from 55 to 100% of at least one alkali metal silicate exhibiting an Si/alkali metal weight ratio which varies from 0.3 to 2, from 0 to 35% of at least one plasticizing agent, and from 0 to 10% of one or more additives. Fibrous products can obtained from this composition, in particular based on mineral fibers, such as mats, screens, woven fabrics, in particular painter's canvases, and knitted fabrics.

Claims

1. A fibrous product coated with an aqueous inorganic or hybrid binder composition, wherein the product is in the form of a mat of mineral fibers, of a screen of mineral fibers, of a woven fabric of mineral fibers, or of a knitted fabric of mineral fibers, and the aqueous inorganic or hybrid binder composition comprises (as % by weight of solid matter): from 55 to less than 100% of at least one alkali metal silicate exhibiting an Si/alkali metal weight ratio which varies from 0.3 to 2, from more than 0 to 35% of at least one plasticizing agent chosen from the group consisting of copolymers of styrene and butadiene, homopolymers and copolymers of alkyl (meth)acrylates, copolymers of alkyl (meth)acrylates and styrene, copolymers of (meth)acrylic acid and styrene, poly(vinyl acetate)s, silicones, and siliconates, and from 0 to 10% of one or more additives.

2. The product as claimed in claim 1, wherein the alkali metal silicate is a potassium or sodium silicate.

3. The product as claimed in claim 1, wherein the alkali metal silicate has an Si/alkali metal weight ratio of greater than 0.5.

4. The product as claimed in claim 1, wherein the plasticizing agent has a glass transition temperature of less than 0 C.

5. The product as claimed in claim 1, wherein the proportion of plasticizing agent is at most equal to 25%.

6. The product as claimed in claim 1, wherein the plasticizing agent is a polydimethylsiloxane and its content is from more than 0 to 2%.

7. The product as claimed in claim 1, wherein said composition comprises more than 0% of said one or more additives, and wherein the one or more additives comprises bis(3-triethoxysilylpropyl) tetrasulfide.

8. The product as claimed in claim 1, wherein the product is in the form of a woven fabric of mineral fibers.

9. The product as claimed in claim 1, wherein the product is in the form of a mat of mineral fibers.

10. The product as claimed in claim 9, wherein the fibers exhibit a length at most equal to 150 mm.

11. The product as claimed in claim 9, wherein the product exhibits a weight per unit area which varies from 10 to 1100 g/m.sup.2.

12. The product as claimed in claim 1, wherein the product includes from 5 to 50% by weight of inorganic or hybrid binder.

13. The product as claimed in claim 1, wherein the alkali metal silicate has an Si/alkali metal weight ratio that varies from 1.2 to 1.6.

14. The product as claimed in claim 9, wherein the fibers exhibit a length at from 50 to 70 mm.

15. The product as claimed in claim 9, wherein the product exhibits a weight per unit area which varies from 35 to 80 g/m.sup.2.

16. The product as claimed in claim 1, wherein the product includes from 10 to 45% by weight of inorganic or hybrid binder.

17. The product as claimed in claim 1, wherein the at least one alkali metal silicate exhibits an Si/alkali metal weight ratio which varies from 0.3 to 1.5.

18. The product as claimed in claim 8, wherein the woven fabric of mineral fibers is a painter's canvas.

19. The product as claimed in claim 1, wherein the product is in the form of a screen of mineral fibers.

20. The product as claimed in claim 1, wherein the product is in the form of a knitted fabric of mineral fibers.

21. A fibrous product coated with a binder composition, wherein the fibrous product is a woven fabric which is provided in the form of a painter's canvas comprising glass yarns composed of a plurality of glass filaments, and wherein the binder composition is an aqueous inorganic or hybrid binder composition, comprising (as % by weight of solid matter): from 55 to 100% of at least one alkali metal silicate exhibiting an Si/alkali metal weight ratio which varies from 0.3 to 2, from 0 to 35% of at least one plasticizing agent, and from 0 to 10% of one or more additives.

22. The fibrous product as claimed in claim 21, wherein the glass yarns exhibit a linear density which varies from 50 to 500 tex and exhibits a weight per unit area which varies from 30 to 1000 g/m.sup.2, and wherein the binder composition comprises from more than 0 to 35% of said at least one plasticizing agent.

Description

EXAMPLES 1 TO 6

(1) These examples illustrate the manufacture of mats of glass fibers.

(2) Potassium silicate in aqueous solution, a latex of styrene/butadiene resin and optionally a polydimethylsiloxane are mixed in the proportions appearing in table 1, expressed as % by weight of the solid matter. The pH of the mixture is adjusted to 11 with sodium hydroxide solution. Water is added to the mixture, so as to obtain a content of solid matter equal to 15%.

(3) A mat of fibers of glass C (Grade GF/C Glass Microfiber Filter Binder Free sold by Whatman) is impregnated by immersion in the abovementioned aqueous binder composition. After having removed the excess binder, the mat is placed in a drying oven at 200 C. for 3 minutes.

(4) The properties of the mats obtained are given in table 1 in comparison with a mat treated with a melamine/formaldehyde resin (Reference) under the same conditions, except that the duration of the treatment in the drying oven is equal to 5 minutes.

(5) Examples 1 and 3 exhibit a good tensile strength combined with a greater stiffness than that of the Reference. The addition of plasticizing agent makes it possible to reduce the stiffness of the mat (examples 2 and 4, to be compared with examples 1 and 3), without damaging the tensile strength (example 4).

(6) Example 4 represents a good compromise between the tensile strength and the stiffness of the mat, similar to the performance of the Reference.

(7) The presence of polydimethylsiloxane in example 5 makes it possible to reduce the stiffness of the mat by 74.7%, with respect to example 4, while retaining an acceptable tensile strength.

(8) The stiffness of the mat of examples 1, 3 and 6 decreases when the Si/P ratio decreases. The choice of the Si/P ratio makes it possible to control the properties of the mat, both its tensile strength and its stiffness.

EXAMPLES 7 TO 14

(9) A mat is manufactured under the conditions of examples 1 to 6, modified in that the binder composition has the composition given in table 2.

(10) The mats of examples 7, 8, 10 to 12 and 14, and also the Reference mat, are subjected to the test of resistance to fire. The results appear in table 2.

(11) Examples 7 to 10 and 14 according to the invention exhibit a similar tensile strength to the Reference, at an equivalent content of binder. The performances toward fire of the mats according to the examples are better than the Reference, whether in terms of propagation distance or of 15 cm propagation time.

EXAMPLES 15 TO 17

(12) These examples illustrate the manufacture of painter's canvases.

(13) The binder composition is prepared by mixing the compounds appearing in table 3, in proportions expressed as % by weight of the solid matter. The solid matter content in the aqueous binder composition is equal to 13%.

(14) A painter's canvas composed of woven glass yarns is impregnated by immersion in the abovementioned binder composition. The painter's canvas is a woven fabric having a satin weave composed of 4.5 bulked yarns of 330 tex per cm, as weft, and 7.9 yarns of 68 tex per cm, as warp. The weight per unit area of the canvas is equal to 200 g/m.sup.2.

(15) After having removed the excess binder, the impregnated painter's canvas is placed in a drying oven at 200 C. for 90 seconds.

(16) The amount of binder represents 20% of the weight of the painter's canvas obtained.

(17) The properties of the painter's canvases obtained appear in table 3, in comparison with a painter's canvas treated under the same conditions with a melamine/formaldehyde resin (Reference).

(18) The measurements of resistance to fire for examples 15 and 16 and the Reference are given in table 3.

(19) Examples 15 and 16 exhibit a comparable stiffness to that of the Reference. The addition of a coupling agent (example 17) makes it possible to obtain a higher tensile strength and a higher stiffness than those of the Reference.

(20) The properties of resistance to fire of examples 15 and 16 are far superior to those of the Reference.

(21) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 Ref. Potassium silicate.sup.(1) 100 75 Potassium silicate.sup.(2) 100 75 73 Potassium silicate.sup.(3) 100 Styrene/butadiene copolymer.sup.(4) 25 25 25 Polydimethylsiloxane.sup.(5) 2 Content of binder (% by weight) 47.2 47.0 43.1 47.6 43.8 45.0 45.0 Tensile strength (N) 86.7 n.d. 90.0 96.5 68.1 33.3 109.0 Stiffness (mN) 98.9 53.2 89.3 60.0 15.2 33.0 65.4 .sup.(1)Reference Betol K42T, sold by Woellner (weight ratio Si/P = 1.9; P meaning potassium), .sup.(2)Reference Betol K5020T, sold by Woellner (weight ratio Si/P = 1.6; P meaning potassium) .sup.(3)Reference Betol K57M, sold by Woellner (weight ratio Si/P = 0.6; P meaning potassium) .sup.(4)Reference Lipaton SB 29Y46, sold by Synthomer (latex) .sup.(5)Reference Betolin AH250, sold by Woellner n.d.: not determined

(22) TABLE-US-00002 TABLE 2 Example 11 12 13 Example 7 8 9 10 (comp.) (comp.) (comp.) 14 Ref. Potassium silicate.sup.(1) 100 Potassium silicate.sup.(2) 100 90 80 70 60 50 25 Styrene/butadiene copolymer.sup.(4) 10 20 30 40 50 75 Content of binder (% by weight) 47.4 48.5 47.3 47.4 47.1 47.8 44.0 47.2 45.0 Tensile strength (N) 120.4 100.0 105.9 107.4 109.2 105.6 85.5 86.7 109.0 Propagation distance (mm) Section 15 40 n.d. 80 Total Total n.d. 20 Total Surface 30 50 n.d. 70 Total Total n.d. 30 n.d. 15 cm propagation time (s) Section n.f.p. n.f.p. n.d. n.f.p. 6 6 n.d. n.f.p. 3 Surface n.f.p. n.f.p. n.d. n.f.p. 10 9 n.d. n.f.p. n.d. .sup.(1)Reference Betol K42T, sold by Woellner (weight ratio Si/P = 1.9; P meaning potassium) .sup.(2)Reference Betol K5020T, sold by Woellner (weight ratio Si/P = 1.6; P meaning potassium) .sup.(4)Reference Lipaton SB 29Y46, sold by Synthomer (latex) n.d.: not determined n.f.p.: no flame propagation

(23) TABLE-US-00003 TABLE 3 Example 15 16 17 Reference Potassium silicate.sup.(2) 100 75 75 Styrene/butadiene copolymer.sup.(4) 25 24 Coupling agent.sup.(6) 1 Tensile strength (N) 202.7 219.4 542.1 465.4 Stiffness (mN) 58.4 59.5 90.1 64.8 Propagation distance (mm) Section 30 50 n.d. Total Surface 30 60 n.d. Total 15 cm propagation time (s) Section n.f.p. n.f.p. n.d. 9 Surface n.f.p. n.f.p. n.d. 18 .sup.(2)Reference Betol K5020T, sold by Woellner (weight ratio Si/P = 1.6; P meaning potassium) .sup.(4)Reference Lipaton SB 29Y46, sold by Synthomer (latex) .sup.(6)Reference Si69, sold by Evonik Industries AG n.d.: not determined n.f.p.: no flame propagation