Glass yarn for reinforcing organic and/or inorganic materials
View Patent ↗The invention relates to glass reinforcement strands, the composition of which comprises the following constituents in the limits defined below, expressed as percentages by weight: 59 to 63% SiO 2 ; 10 to 16% Al 2 O 3 ; 16 to 23% CaO; 1 to 3.2% MgO; 0 to 2% Na 2 O+K 2 O+Li 2 O; 0 to 1% TiO 2 ; 0.1 to 1.8% B 2 O 3 ; 0 to 0.5% Li 2 O; 0 to 0.4% ZnO; 0 to 1% MnO; and 0 to 0.5% F. These strands have improved properties in terms of mechanical strength, acid resistance and high-temperature resistance for a low-cost composition. The invention also relates to a process for producing the said strands and to the composition allowing them to be produced.
1. A glass strand, comprising the following constituents in the limits defined below, expressed as percentages by weight:
SiO 2
59
to 63
Al 2 O 3
10
to 16
CaO
16
to 23
MgO
1
to less than 3.2
Na 2 O + K 2 O
0
to 2
TiO 2
0
to 1
B 2 O 3
0.5
to 1.5
Li 2 O
0
to 0.5
ZnO
0
to 0.5
MnO
0
to 1
and which does not comprise F or Li.
2. The glass strand according to claim 1 , formed from a glass melt obtained by melting a batch characterized in that the said batch includes borax.
3. The glass strand according to claim 1 , characterized in that the TiO 2 content is greater than or equal to 0.5%.
4. The glass strand according to claim 1 , wherein when the TiO 2 content is less than or equal to 0.5%, the SiO 2 content is greater than 60.5%.
5. The glass strand according to claim 1 , wherein the MgO content is greater than or equal to 2.2%.
6. A composite, comprising glass strands, organic material, inorganic material and the glass strand as defined in claim 1 .
7. A fitting for an exhaust system, the glass strand as defined in claim 1 .
8. A glass composition suitable for producing glass reinforcement fibres, which comprises the following constituents in the limits defined below, expressed as percentages by weight:
SiO 2
59 to 63
Al 2 O 3
10 to 16
CaO
16 to 23
MgO
1 to less than 3.2
Na 2 O + K 2 O
0 to 2
TiO 2
0 to 1
B 2 O 3
0.5 to 1.5
ZnO
0 to 0.5
MnO
0 to 1
and which does not comprise F or Li.
9. A process for manufacturing glass strands, comprising attenuation into the form of one or more webs of continuous filaments from a multiplicity of molten glass streams emanating from a multiplicity of orifices placed at the base of one or more bushings, and of assembling the said filaments into one or more strands that are collected on a moving support, the molten glass feeding the bushings having a composition according to claim 8 .