FI87452B - Glass fibre having improved heat resistance and process for its production - Google Patents

Description

! 87452

Glass fiber with improved temperature resistance and a method of making the same

It is known to treat glass fibers with acid to improve temperature resistance. This results in a loss of weight because the added ingredients are extracted from the glass to lower the melting point.

However, this acid treatment results in a significant decrease in strength. For example, when 20% of the initial weight is extracted from the glass fiber by acid treatment, only about 10% of the initial strength remains (this means, for example, a reduction in strength from 300 N to about 30 N). As the temperature resistance also rises to about 900 ° C, such fibers can no longer be processed into usable products or utilized as usable products due to their low residual strength.

Therefore, in connection with acid extraction, tempering and tempering are carried out to process glass fiber or chromium compounds, or very pure water glass is added already in acid extraction and then treated for rejuvenation with organic complexing agents of metal complexes and then heated to temperatures between 600 ° C and 1000 ° C ( published DE-AS 28 38 476). Although this results in a slight loss of strength of the treated glass fibers, the strength thus obtained is still not sufficient for many uses, e.g. for processing the fibers in a strip weaving machine. Therefore, the known acid treatments can only be used for finished products, e.g. finished fabrics or tapes, but not for glass fibers, which have to be further processed in textile machines.

DE-AS 1 026 925 discloses practically complete extraction of all acid-soluble parts in the glass fiber, which corresponds to a washing degree of about 45%. Similarly, DE-AS 28 29 413 discloses that the SiO2 content of the glass fiber is extracted to between 90% and almost 100%, after which metal salts are then added and these are first converted into their hydroxides and then by annealing into oxides. Also, such glass fibers can no longer be woven, but are compressed into worms, for example.

In addition, as a result of the acid treatment of the glass fibers, an increased amount of glass dust is also formed in the known post-processing, further processing, because small pieces of glass fiber break and go into the air as dust, which is dangerous in occupational medicine.

Therefore, a layer is formed to increase the heat resistance of the glass fibers, but at the same time substantially reduce the strength loss, so that they can be further processed in textile machines and further substantially reduce or substantially eliminate the risk of dusting.

This is achieved in that the fiber released from the acid-soluble constituents by 1 to 30% by weight has, in addition to a possible coloring coating, a permanent, moisture- and water-vapor-resistant, thin, elastic coating and a residual water content of 5 to 10% by weight, preferably 5 to 7% by weight. -%. Preferably, the fibers are released from 2 to 20% by weight, in particular from 2 to 15% by weight, of acid-soluble constituents, in which case E-glass and in particular glass fibers with a thickness of at most 9 μπι and more preferably 6 μπι are preferably treated.

This fiberglass is prepared by heating 20 air temperature jumps in acid, performing extraction and cooling relatively slowly, rinsing the extracted fiberglass, and then applying an adhesive solution to form a continuous waterproof cover on the fiberglass to protect this fiberglass before complete drying. In particular, a method of making these glass fibers is to slowly heat the fibrous-acid mixture over a period of 1/2 to 3 hours to temperatures in the range of 50 ° C near the boiling point of the acid, maintain it at that temperature, and then slowly cool to ambient temperature. in the range above 50 ° C, both heating and cooling, and in order to achieve an extraction rate of at least 1% by weight to at most 30% by weight of the original fiber weight, the treatment is carried out possibly under pressure and the glass fiber thus extracted after washing with acid radicals, possibly with addition of bases and optionally after providing a characteristic color tone, is provided as a water vapor-resistant film with a drying layer.

With an extraction rate of 6 μπι: η and 9 μπκη thick fibers, e.g. 20%, usually with a residual glass strength of 10%, such a quality of acid treatment and the application of such a plastic film to prevent the extracted glass from drying can achieve a standard extracted glass fiber material. An increase in strength of 300-400%, i.e. from about 30 N to about 120 N for fibers with a thickness of 9 μιη: η and for fibers with a thickness of 6 μιη: η up to about 50% of the original strength. At the same time, good dust binding occurs and the fibers are virtually non-sticky when processing dust in textile machines.

For acid extraction, inorganic acids are preferably used which do not form any sparingly soluble salts with the glass components, but also sufficiently strong organic acids such as oxalic acid, tartaric acid and trichloroacetic acid are useful. Nitric acid is preferred.

The degree of washing should be at least 1% by weight and at most 30% by weight of the initial weight of the glass fibers, preferably 2-20% and in particular 2-15%. Ordinary E-glass fiberglass-20 has a temperature resistance of about 600 ° C. At this temperature, the fiberglass then loses its strength.

In the case of e-glass, at a washing rate of 2%, the operating temperature rises to more than 700 ° C, at a washing rate of 10-12% above 750 ° C, at a washing rate of about 20% to about 900 ° C and at a washing rate of 30% to more than 1000 ° C, but there are always the difficult processing problems mentioned at the beginning. The resinization of the fiber after washing prevents these processing problems, since always said increased strength occurs in the case of simultaneous dust binding.

: 30 The thickness of the glass fiber used is preferably 9 μπι or less, in particular 6 μια.

Most preferably, the glass is E-glass. Because C-glass is chemically more durable and under conditions where 20% weight loss is achieved with E-glass, C-glass has only 2-3 35% weight loss, in which case stricter conditions must be used.

However, these can be found out in a few preliminary experiments.

In the case of e-glass, the treatment is preferably carried out according to the desired degree of extraction as follows:

The acid is usually used at a concentration corresponding to 4 87452 of about 10-200 g of 52/53% HNO3 pro 1 part extraction solution. When extracted from one to 10%, the concentration of this acid is about 10-100 g / l and at the desired extraction rates of 10-30% the concentration of the acid is 100-200 g / l. Preferably, for a weakly extracted fiber 5 having an extraction rate of about 2% by weight, an amount of 12-15 g pro 1 52/53% nitric acid is used. By adding 1-3 g / l of acid-resistant wetting agent, the amount of acid can be reduced by 10-20% at the same time.

The usual treatment is from about 60 ° C very close to the boiling point of the solution, preferably about 80 ° C. The treatment time is 1-2 h, depending on the temperature and the concentration of the acid, but preferably for about 30 minutes to warm from room temperature to 80 ° C, then kept for about 30 minutes at 80 ° C and then cooled for 15 minutes to about 50 ° C. . Further cooling can then occur more rapidly, possibly by conducting cold water. Temperature jumps during heating and cooling above 50 ° C must be avoided as they may adversely affect the strength.

20 A neutralizing agent, ie preferably ammonia, is added to the rinsing bath (water). After about 10 minutes of treatment, the pH is preferably 8, with all acid radicals bound.

As mentioned, with less fast extracting acids and in the case of C-glass, temperatures can be further raised and / or times extended to achieve the desired degree of extraction.

However, since for operational reasons it is simplest to keep the time and temperature program always constant-30 Mana, the different washing degrees are most easily affected by the variation of the acid concentration, as explained in more detail.

The rinsed neutralized glass fiber can then be dyed, if desired, for example to give them a characteristic color, in which case basic dyes are particularly suitable.

The still moist glass fibers are then provided with an adhesive solution, preferably an aqueous dispersion. This adhesive solution must then be formed on the glass fibers as a moisture-proof cover and precisely in such a way that when the adhesive solution crosslinks, usually under the influence of heat, the glass fibers do not dry completely but contain at least 5% residual moisture and remain in subsequent storage.

Suitable for the adhesive solution are, in principle, all materials which form a virtually waterproof and water vapor-tight coating on the glass fiber. Most preferred are thermosetting, self-crosslinking copolymer resin derivatives, especially in admixture with polysiloxanes and polyalkenes, as used for the high marsh processing of all fiber grades and knits. Such copolymers usually crosslink reactively at temperatures starting from 130 ° C. But also silicone elastomers, polyvinyl alcohol dispersions and other elastic lacquer systems, e.g. polyurethane, are useful when they meet the above conditions.

In any case, compounds which cure from aqueous systems and retain a certain durability are preferred.

One preferred agent for carrying out the process is the use of the conventional AZ process for acid treatment in a textile mill. In this case, the glass fiber, preferably in the form of commercially available dye sides, is immediately placed in an HT dyeing device, as is also customary in an HT dyeing plant, and hap-25 po is recycled (such as an otherwise dye bath) from the inside outwards or alternatively vice versa. The yarn can then be processed immediately on the dyeing sides.

For the concept of extraction method or AZ method see: 30 Ullmann's Encyklopädie der technischen Chemie, 3rd ed.,

Bd. 7, pages 9-11.

The HT device is operated at low pressure, which means that the bypass in the normal application methods of this dyeing device remains open. When, for example, in the case of C-glass, it was found that no sufficient extraction is thus achieved, i.e. no sufficient weight loss, it is also possible to operate at high pressure with the bypass closed.

Drying of the glass fiber, which must already take place after the adhesive solution has been applied, which adhesive solution then, for example, crosslinks, can take place in any usual manner. However, also here an ordinary drying unit is advantageous for the HT device, because in this way the capacity of both units is balanced with respect to each other and the drying can be performed very quickly.

In drying, it is only important that the fiber does not dry until the moisture-proof coating has hardened and thus the glass fiber is protected before complete drying, i.e. crosslinking or the formation of a generally water vapor-resistant layer on the glass fiber surface is complete before the glass fiber (below the water vapor layer) is dried below. 5-7%.

As mentioned above, the degree of extraction can be influenced most simply by varying the acid concentration. Another possibility is to lower the color bath ratio. While a wash rate of 10-30% 1: 5 (weight ratio product: bath) is preferred for wash levels, a color bath ratio of 1: 4 is preferred for lower wash levels. When the color bath ratio is heated to 20 ° C, the degree of washing of the glass fibers in the bath increases with the same acid concentration.

The addition of acid-resistant crosslinking agents, such as nonionic crosslinking agents, e.g. alkyl polyglycoethers (for example, Peren's GNS) can reduce the amount of acid at the same constant washing rate by 10-20%, apparently: ** · because the coils ventilate faster and better and the acid enters passes better to the fiber and the washed material is better transported away.

Very interesting is the washing degree of about 2%, 30 e.g. 2-2.5% by weight, because here it is already possible to increase the temperature resistance to more than 700 ° C, while the strength value of the untreated fiber drops to about half of the initial strength of the water vapor-resistant coating. then rises to almost 90 to 35 percent of initial strength. In this case, with a color bath ratio of 1: 4, an amount of 12 g / l of 52/53% nitric acid and 1 g / l of acid-resistant crosslinking agent is sufficient, whereas without this crosslinking agent, an amount of acid of 15 g / l with a constant washing time and temperature program, e.g. 7,847,42 have also been reported above for a wash rate of 10-30%.

Raising and lowering the treatment temperature to a preferred temperature of about 80 ° C also indicates an increase and decrease in the washing rate, as well as an increase or decrease in the treatment time, but these measures are not considered advantageous because it is simpler in practice to follow a once set temperature and time program. and the effects of temperature and time change are less advantageous than increasing the acid concentration and / or changing the color bath ratio. On the other hand, since it is difficult to always completely fill the device, the use of the same glass-fiber products also changes the color bath ratio as little as possible, varying the addition of acid-resistant crosslinking agent 15 and in particular and preferably the acid concentration with small desired changes.

When the strengths do not decrease as sharply as at high washing rates, even at high washing rates, however, the decrease in strength without finishing, application of a water vapor-tight coating and above all dust formation in processing for technical processing in textile bricks to prevent the health hazard caused by the formation of dust.

The following examples illustrate the invention.

Example 1

An HT dyeing device of ordinary construction (acid-resistant) with a color bath volume of 2000 l was filled with 2000 ·. 30 liters of about 10% by weight nitric acid (300 l of 52/53% nitric acid and 1700 l of water). Fiberglass halves (fiber thickness 9 μια) were then inserted as usual for HT staining (color bath ratio was 1: 5).

The charged color bath was then brought from 25 ° C (initial temperature) to 80 ° C for 30 minutes and then held at 80 ° C for 30 minutes. The temperature was then brought to 50 ° C by indirect cooling over 15 minutes and then further cooled by passing cold water. In this case, and also in the following β 37452 work steps, the bypass was always open. Cold water was introduced by rinsing in the overflow and then the bath was drained off.

The contents were then rinsed once cold and the bath counted again and finally ammonia was added to the rinsing bath to bring the entire contents to pH 8 and then the rinsing bath was drained.

The treated glass fiber was then stained cold for 10 minutes with Astrazonblau 10 BG (30 g / color bath content) and then the spools were rinsed by filling the device once with water and draining the water.

The post-treatment was carried out immediately in the same apparatus in half with a dispersion containing 10 g / l of a thermosetting, 15 self-crosslinking copolymer resin (e.g. the commercial preparation Pretavyl 9179 as an anionic, white, easy-to-flow dispersion containing 27% with stirring in water in all proportions, starting at temperatures of 130 ° C). As a dispersant, 1 g / l Solpon BS (commercially available Fa. Dr. Th. Böhme detergent) was added to the paint bath. The glass fiber sides were treated with an adhesive solution for 30 minutes at 25 ° C in an HT dye. The material was then inverted from the post-treatment bath and dried after HT in a subsequent flash drier by pressing for 1 minute at 130 ° C and then dried for 45 minutes at 130 ° C and simultaneously condensed. As with dyeing, the air flow from the inside to the outside during drying.

This treatment resulted in a weight loss of the glass fiber of about 20% and an amount of adhesive solution of about 1% by weight of the glass fiber.

The strength of the dried glass fiber was 111 N relative to the initial strength of 300 N of the introduced glass fiber, and the acid-treated glass fiber, which was dried before the adhesive solution was placed in place, had a residual strength of 28 N.

Example 2

The experiment was repeated in a smaller HT dye, using 97.5 L of 52/53% nitric acid in a 635 liters (87,852 r) HT net. The color bath ratio was again 1: 5. 128 kg of EC-thin glass fiber 9/720 tex x 3 was used. Recycling of the treatment acid took place from the inside to the outside with the bypass open. Again, it was heated for 30 minutes from room temperature to 80 ° C. The pressure at which it settled was about 2 bar. The product was kept at 80 ° C for 30 min, then cooled for 15 min by indirect cooling to 60 ° C and then by slowly passing cold water over the dosing vessel for a further 15 min to about 30 ° C.

The first rinsing bath contained 4 g / l of a 25% ammonia solution. Rinsing was done for 10 min with cold ammonia water. It was then rinsed once more with a solution containing 7 g of Remacrylblau 3 G (identical to Astrazon-15 blau BG) to obtain a characteristic color tone and for 10 min in the cold. The water was then centrifuged for 30 min to give a residual moisture of about 18%.

The product was then post-treated again with 10 g / l Pretavyl 9179 spez. and 1 g / l of Solpo BS for 30 min at 25 ° C and the material turner (fiberglass coils) was removed from the finishing bath and dried in a flash drier as in Example 1 and the coating condensed.

The strength of this product was also about 300 N before treatment, the tensile strength was still 113.7 N in centrifuged moisture, and after post-treatment and drying with condensation the strength was 97.0 N.

After complete drying of the oven-dried product, which was not post-treated with the adhesive solution, the tensile strength was only 28.75 N.

'30 For the comparative test, which was carried out in the same way as in Example 2, however, it was not heated to a crosslinking temperature of 130 ° C, but only to 100 ° C when dried, the strength after drying being only 28.75 N.

In both the products of Example 1 and Example 2, there was virtually no dust formation when processing 35 yarns in the strip weaving mill, while the comparative test product, which had not formed any moisture-resistant, fully crosslinked adhesive solution, showed heavy dusting and had a tensile strength of 28 N. 10 87 452 low that the test, when using yarn in a ribbon weaving mill, had to be interrupted.

Example 3 As a control, Example 1 was repeated and, in the same manner as in Example 1, etched with acid, rinsed, neutralized and stained.

The dyed product was then divided into three batches, which were further processed as follows: 10 First batch

The spools were dried at 100 ° C and then spools with glass fiber strands as indicated in Example 1 were post-treated in a bath containing 10 g / l Pretavyl 9179 spez. dispersion and 1 g / l Solpo BS as dispersant, 30 min at 25 ° C and then dried in an HT flash dryer as indicated in Example 1.

The final strength was 87 N.

Second round

The spools were treated to centrifugal moisture, i.e. without intermediate-20 drying before gluing, but otherwise identical to batch 1. The final strength here was 113 N.

In both cases, the strength of the unglued fiber after storage and drying was 30 N.

Third batch This was post-treated as indicated in Example 1, dewatered in a centrifuge and then dried in an HT flash dryer as indicated in Example 1, however using only 100 ° C (instead of 130 ° C). In this case, no condensation of the adhesive occurred. The final strength was only 28 N, as in the case of unglued dried fiber.

The experiment shows that it is important to provide a moisture- and water-vapor-resistant coating on the surface of the fiber and to obtain a residual water-35 content of at least 5%, in particular 5-7%, in the glass fiber during the treatment.

Due to the effect of centrifugation, there is a risk that the post-treatment agent (moisture-resistant adhesive) is distributed irregularly on the surface of the fiber, which in these experiments could be responsible for the poorer result.

Example 4

Example 1 was repeated identically, however, using a wire thickness of 6 μ on 5 glass fiber sides. In this case, the washing rate was about 20%.

These fibers had an initial strength of 450 N and a final strength after condenser condensation of 241 N, indicating that better strength retention can be achieved by implementing the method for thin fibers. Therefore, the use of glass fibers with a thickness of 6 μ is considered advantageous, in any case in the case of high washing rates.

Example 5 This example was performed in the same manner as in the 2000 liter HT apparatus used in Example 1 with glass fiber EC-9/720 tex x 2 as the starting material with a color bath ratio of 1: 5 and an 52/53% acid concentration of 12 g HNO 3 pro 1 bath and 1 g of pro non-iogenic alkyl polyglycoether Pe-20 renin GNS under the same time and temperature conditions as shown in Example 1. The extraction rate was 2.1%. The tensile strength of the starting material was 294 N, which halved due to the acid extraction. After post-treatment according to the invention, a dispersion containing 10 g / l of Pretavyl 9179 25 spez. and 1 g / l of Solpo BS as a dispersant, as in Example 1, and the simultaneous crosslinking of the adhesive solution gave a final strength of 263 N, which allowed a proper and dust-free further processing in a strip weaving machine.

30 Example 6

Example 5 was repeated otherwise identically, but at an acid concentration of 26 g / l instead of 12 g / l, giving a washing rate of 5.2%. The initial strength of 294 N decreased to 50 N due to extraction and increased to 35 90 N due to post-treatment.

The formation of fine dust in the testing process increases the degree of washing in the untreated state. In the post-treated material, practically no formation of fine dust is observed in the further treatment.

i2 87452

When Examples 4 and 5 were repeated without the addition of Perenin, the acid concentration required in the first case was 15 g / l and in the second case 31 g / l to achieve a washing rate of 2% or 5% otherwise under the same conditions.

Claims (10)

A glass fiber with improved temperature resistance, characterized in that the fiber released from the acid-soluble constituents by 1 to 30% by weight, in addition to a possible coloring coating, has a permanent, moisture- and water-vapor-resistant, thin, elastic coating and residual water content 5-10% by weight, preferably 5-7% by weight. Glass fiber according to Claim 1, characterized in that it is released from 2 to 20% by weight, in particular from 2 to 15% by weight, of acid-soluble constituents. Process for producing a glass fiber according to claim 1 or 2, characterized in that the fibrous acid mixture is slowly heated over a period of 1/2 to 3 hours to temperatures in the range from 50 ° C near the boiling point of the acid, kept at this temperature and then slowly cooled to ambient temperature. temperature jumps in the range above 50 ° C during both heating and cooling, and that in order to achieve an extraction rate of at least 1% by weight to at most 30% by weight of the original fiber weight, the treatment is possibly carried out under pressure, and that the glass fiber thus extracted after washing the acid radicals, it is provided with a water-vapor-resistant film with a drying layer, possibly under the addition of bases and after obtaining a possible characteristic color. Process according to Claim 3, characterized in that the extraction rate is adjusted to a value of 2 to 20%, in particular 2 to 15% by weight. Method according to Claim 3 or 4, characterized in that thermally crosslinkable plastic derivatives are used for the water-vapor-resistant surface film. Process according to Claim 3, 4 or 5, characterized in that the acid treatment, washing and drying are carried out in an HT dyeing apparatus for the extraction-dyeing process under normal conditions. '35 A method according to claim 6, characterized in that the placement of the water vapor barrier coating on the glass fiber is performed in an HT dyeing device as an aqueous dispersion and the thus treated fiber is removed from the device and after possible dewatering is transferred to an HT dryer 1487452 and condensed sufficiently. temperature, in particular at least 130 ° C. Process according to Claims 3 to 7, characterized in that an amount of acid is used, corresponding to 10 to 200 g of 52/53 5% HNO 3 per liter bath, in particular 10 to 100 g per liter. Process according to one of Claims 3 to 8, characterized in that 1 to 3 g / l of acid-resistant crosslinking agent are added to the acid bath. A method according to claim 9, characterized in that the amount of acid placed at the same time is reduced by 10-20%. 15 87452