Glass yarns, composite thereof, method for making same and reinforcing glass composition

1. Reinforcing glass yarn, the composition of which comprises the following constituents, within the limits defined below, expressed in percentages by weight:

SiO 2

54.5 to 58%

Al 2 O 3

12 to 15.5%

SiO 2 + Al 2 O 3

70 to 73%

CaO

17 to 25%

MgO

0 to 5%

RO = CaO + MgO

21 to 28%

R 2 O = Na 2 O + K 2 O + Li 2 O

up to 2%

TiO 2

less than 1%

Fe 2 O 3

less than 0.5%

B 2 O 3

up to 3%

F 2

less than 1%

and such that the ratio R 1 =Al 2 O 3 /CaO is less than 0.7, and when SiO 2 is greater than 57% the amount of boron oxide B 2 O 3 is greater than 2%,

wherein the composition further satisfies the criterion:

2.35<R 2 =(SiO 2 +Al 2 O 3 )/(RO+R 2 O+B 2 O 3 )<2.70,

a T (log 2.5) of at least 1300° C.,

its liquidus temperature is less than or equal to 1200° C.,

and its fiberizing temperature range is greater than 100° C.

2. Glass yarn according to claim 1 , wherein the composition has a silica, SiO 2 , content such that SiO 2 ≦57%.

3. Glass yarn according to claim 1 , wherein the composition has a boron oxide, B 2 O 3 , content such that:

B 2 O 3 ≦0.5%.

4. Glass yarn according to claim 1 , wherein the composition has a boron oxide, B 2 O 3 , content such that:

0.5%≦B 2 O 3 ≦3%.

5. Glass yarn according to claim 1 , wherein SiO 2 +Al 2 O 3 is 72%.

6. Glass yarn according to claim 1 , wherein SiO 2 +Al 2 O 3 is less than 72%.

7. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

56.5%

Al 2 O 3

15%

SiO 2 + Al 2 O 3

71.5%

CaO

23%

MgO

2%

RO

25%

R 2 O

1%

B 2 O 3

2%

R1

0.65%

R2

2.55%.

8. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

55%

Al 2 O 3

15%

SiO 2 + Al 2 O 3

70%

CaO

24%

MgO

3%

RO

27%

R 2 O

1%

B 2 O 3

1.5%

R1

0.63%

R2

2.37%.

9. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

58%

Al 2 O 3

14%

SiO 2 + Al 2 O 3

72%

CaO

21.5%

MgO

1.5%

RO

23%

R 2 O

2%

B 2 O 3

3%

R1

0.65%

R2

2.57%.

10. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

58%

Al 2 O 3

14%

SiO 2 + Al 2 O 3

72%

CaO

21.5%

MgO

3%

RO

24.5%

R 2 O

1%

B 2 O 3

2.5%

R1

0.65%

R2

2.67%.

11. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

58%

Al 2 O 3

14%

SiO 2 + Al 2 O 3

72%

CaO

22.5%

MgO

2%

RO

24.5%

R 2 O

1%

B 2 O 3

2.5%

R1

0.62%

R2

2.57%.

12. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

57.5%

Al 2 O 3

14%

SiO 2 + Al 2 O 3

71.5%

CaO

23.5%

MgO

1.5%

RO

25%

R 2 O

1%

B 2 O 3

2.5%

R1

0.6%

R2

2.50%.

13. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

57%

Al 2 O 3

15%

SiO 2 + Al 2 O 3

72%

CaO

22%

MgO

3%

RO

25%

R 2 O

1%

B 2 O 3

2%

R1

0.68%

R2

2.57%.

14. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

56.8%

Al 2 O 3

15%

SiO 2 + Al 2 O 3

71.8%

CaO

22.5%

MgO

4%

RO

26.5%

R 2 O

1%

B 2 O 3

0.5%

R1

0.67%

R2

2.56%.

15. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

56.5%

Al 2 O 3

15%

SiO 2 + Al 2 O 3

71.5%

CaO

23%

MgO

2.5%

RO

26.5%

R 2 O

0.1%

B 2 O 3

2.8%

R1

0.65%

R2

2.42%.

16. Glass yarn according to claim 1 , wherein, expressed in percentages by weight:

SiO 2

56.5%

Al 2 O 3

15%

SiO 2 + Al 2 O 3

71.5%

CaO

24%

MgO

2.5%

RO

26.5%

R 2 O

0.1%

B 2 O 3

2%

R1

0.63%

R2

2.5%.

17. Composite consisting of glass yarns and of organic and/or inorganic material(s), wherein said composite comprises glass yarns as defined by claim 1 .

18. Process for manufacturing glass yarns as defined in claim 1 , in which a multiplicity of molten glass streams, flowing out of a multiplicity of orifices arranged at the base of one or more spinnerets, is drawn into the form of one or more sheets of continuous filaments and the filaments are then assembled into one or more yarns which are collected on a moving support.

19. Process according to claim 18 , wherein the molten glass feeding the orifices of the spinneret(s) has the following composition, expressed in percentages by weight:

SiO 2

54.5 to 58%

Al 2 O 3

12 to 15.5%

SiO 2 + Al 2 O 3

70 to 73%

CaO

17 to 25%

MgO

0 to 5%

RO = CaO + MgO

21 to 28%

R 2 O = Na 2 O + K 2 O + Li 2 O

up to 2%

TiO 2

less than 1%

Fe 2 O 3

less than 0.5%

B 2 O 3

up to 3%

F 2

less than 1%

and such that the ratio R 1 =Al 2 O 3 /CaO is less than 0.7, and when SiO 2 is greater than 57% the amount of boron oxide B 2 O 3 is greater than 2%,

wherein the composition further satisfies the criterion:

2.35<R 2 =(SiO 2 +Al 2 O 3 )/(RO+R 2 O+B 2 O 3 )<2.70,

a T (log 2.5) of at least 1300° C., its liquidus temperature is less than or equal to 1200° C., and

and its fiberizing temperature range is greater than 100° C.

20. Process according to claim 18 , wherein the molten glass is obtained from batch materials mixed in suitable proportions, at least some of the said batch materials being glass yarn waste.

21. Process according to claim 20 , wherein the waste is E-glass yarn waste and/or waste from glass yarns comprising:

SiO 2

54.5 to 58%

Al 2 O 3

12 to 15.5%

SiO 2 + Al 2 O 3

70 to 73%

CaO

17 to 25%

MgO

0 to 5%

RO = CaO + MgO

21 to 28%

R 2 O = Na 2 O + K 2 O + Li 2 O

up to 2%

TiO 2

less than 1%

Fe 2 O 3

less than 0.5%

B 2 O 3

up to 3%

F 2

less than 1%.

22. Process according to claim 20 , wherein the waste represents up to 35% by weight of the batch materials.

23. The process according to claim 20 , wherein the glass yarn waste is 5 to 20% by weight.

24. Glass composition suitable for producing reinforcing glass yarns comprising the following constituents, within the limits defined below, expressed in percentages by weight:

SiO 2

54.5 to 58%

Al 2 O 3

12 to 15.5%

SiO 2 + Al 2 O 3

70 to 73%

CaO

17 to 25%

MgO

0 to 5%

RO = CaO + MgO

21 to 28%

R 2 O = Na 2 O + K 2 O + Li 2 O

up to 2%

TiO 2

less than 1%

Fe 2 O 3

less than 0.5%

B 2 O 3

up to 3%

F 2

less than 1%.

wherein the composition further satisfies the criterion:

2.35<R 2 =(SiO 2 +Al 2 O 3 )/(RO+R 2 O+B 2 O 3 )<2.70,

a T (log 2.5) of at least 1300° C.,

its liquidus temperature is less than or equal to 1200° C., and

its fiberizing temperature range is greater than 100° C.