JPH0444033B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for efficiently producing polyester fibers that have excellent adhesion to rubber. Polyester fibers represented by polyethylene terephthalate have excellent properties such as tensile strength and dimensional stability, and are particularly suitable as rubber reinforcing materials for power transmission belts, V-belts, automobile tires, hoses, and the like. However, since polyester fibers have poor adhesion to rubber, rubber materials reinforced with polyester fibers often separate at the interface between the fibers and the rubber during use, resulting in a problem that the durability of the reinforcing effect is short. Various proposals have been made to improve the adhesion of polyester fibers to rubber. Among them, a typical method is to first treat the polyester fibers with a first treatment bath containing an isocyanate compound, and then RFL. This is a two-bath treatment method consisting of treatment in a second treatment bath containing a resorcinol-formaldehyde-rubber latex mixture called . Although the polyester fiber obtained by this two-bath treatment method shows relatively excellent adhesion to rubber, there is still room for improvement, so we aimed to further improve the adhesion by (1) spinning fibers containing an epoxy compound; A method in which a resorcinol-formaldehyde-rubber latex treatment is performed after treatment with an oil agent (Japanese Patent Laid-Open Nos. 48-27017 and 18921-1989)
(2) A method of blending an epoxy compound into the first treatment bath of the above two-bath treatment method (Japanese Patent Publication No. 42-
11482) have been proposed. The use of this epoxy compound increases the number of functional groups on the surface of the polyester fiber, which certainly improves its adhesion to rubber, but especially in the case of method (1) above, the fibers to which the epoxy compound has been added are stretched during the stretching process. When hot drawing is carried out, there is a problem that not only the high temperature hot plate and hot roller become contaminated, leading to yarn breakage and deterioration of yarn quality, but also that the epoxy compound emits smoke, which is unfavorable in terms of environmental hygiene. In addition, although method (2) above does not have the same problems in the stretching process as method (1) above, since the amount of application is inevitably large, it also causes smoke in the heat treatment process after treatment, and furthermore, It has the disadvantage that it does not have the same adhesion properties. Therefore, the use of epoxy compounds is not preferable, and a major challenge is to reduce the amount of epoxy compounds used as much as possible while still achieving excellent adhesion to rubber. Generally, when polyester fibers are melt-spun and drawn, it is essential to apply a spinning oil to the fibers prior to drawing. Since this tends to impair the adhesion effect of the adhesive used subsequently, some proposals have been made to select a specific spinning oil, but the polyester fibers obtained by this method
In particular, it has not yet achieved a high level of adhesiveness suitable for power transmission belts. Therefore, the present inventors conducted intensive studies with the aim of efficiently producing polyester fibers with excellent adhesion to rubber. As a result, the present inventors first treated polyester fibers with a specific spinning oil, and then added them to the above-mentioned two baths. We discovered that by applying this treatment method, it is possible to obtain polyester fibers for rubber reinforcement that do not cause yarn breakage, deterioration of yarn quality, or smoke generation during the drawing process, and have a high degree of rubber adhesion that is particularly suitable for power transmission belts. The invention has been achieved. That is, the present invention provides polyester fibers including A. (a) at least one selected from ethylene oxide and/or propylene oxide adducts of aliphatic amines having 8 to 22 carbon atoms; (b) polyhydric alcohols and ethylene oxide and/or polyhydric alcohols; Contains at least one selected from propylene oxide adducts and (c) dimethylpolysiloxane, and contains 40 to 80 parts of (a) in a total of 100 parts by weight of (a), (b), and (c).
After treatment with a spinning oil containing 10 to 50 parts by weight of (b) and 0.5 to 10 parts by weight of (c), B. treatment with a treatment bath containing an isocyanate compound,
The present invention provides a method for producing polyester fibers for rubber reinforcement, which is then treated in a treatment bath containing a C. resorcinol-formaldehyde-rubber latex mixture. As mentioned above, the treatment steps of the present invention are roughly divided into three steps: A. Spinning oil application step, B. Isocyanate compound treatment step (first treatment bath), and C. RFL treatment step (second treatment bath). However, the polyester fibers to be subjected to the above step A are spun yarns immediately after melt spinning or undrawn yarns obtained by once winding the same, and the polyester fibers to be subjected to the above steps B and C are drawn after passing through the above step A. A yarn made of this yarn, or a cord or woven fabric made of this yarn. It is also possible, of course, to process the yarn in step B, and then to process it in step C after passing through a cord or weaving step. In step A of the present invention, (a) at least one selected from ethylene oxide and/or propylene oxide adducts of aliphatic amines having 8 to 22 carbon atoms, (b) polyhydric alcohols and ethylene oxide and/or polyhydric alcohol adducts; or at least one selected from propylene oxide adducts and
(c) It is essential to use a spinning oil containing dimethylpolysiloxane in a specific proportion. Here, the above (a) ethylene oxide and/or propylene oxide adduct of aliphatic amine having 8 to 22 carbon atoms is the following general formula: (However, R in the formula is a saturated or unsaturated alkyl group or alkylene group having 8 to 22 carbon atoms, x is 0 or 2, y is 0 or 3, n, m, p and q are 1
The tertiary amine is a tertiary amine represented by an integer of 50 to 50, and specific examples include the following. Among component (a), ethylene oxide adducts of aliphatic amines having 12 to 18 carbon atoms are particularly preferably used. Further, specific examples of the above component (b) include glycerin,
Diglycerin, monoalkylglycerin, dialkylglycerin, trialkylglycerin, polyglycerin, trimethylolethane, trimethylolpropane, 1,2,3-pentatriol,
Examples include polyhydric alcohols such as erythritol, pentaerythritol, adonitol, xylitol, sorbitol and mannitol, and ethylene oxide and/or propylene oxide adducts of these polyhydric alcohols. The ethylene oxide and/or propylene oxide usually has 2 to 60 repeating units, especially 5 to 60 repeating units.
45 is used, and the optimum number of moles added to the polyhydric alcohol is usually 10 to 40. Among component (b), ethylene oxide adducts of di- or polyglycerin are particularly preferably used. (c) As dimethylpolysiloxane (silicone oil), it is appropriate to use one with a viscosity of 50 centipoise or less, and in some cases, silicone oil modified with hydroxyl groups, carboxyl groups, epoxy groups, phenol groups, etc. may also be used. can. Among component (c), it is particularly preferable to use an emulsion silicone oil having a concentration of 5 to 40 centipoise. (a) and (b) occupy in the spinning oil used in step A above.
The proportion of (a) and (c) is 40 to 80 parts by weight, especially 50 to 80 parts by weight.
70 parts by weight, (b) 10 to 50 parts by weight, especially 10 to 40 parts by weight, and (c) 0.5 to 10 parts by weight, especially 2 to 6 parts by weight (total 100 parts by weight), and (a) component If the amount of component (b) is too low, the adhesiveness will decrease, and if the component (b) is too large, the adhesiveness will be good, but thread breakage during stretching will increase, which is not preferable. Furthermore, if the proportion of component (c) is less than 0.5 parts by weight, color breakage during stretching increases, and if it exceeds 10 parts by weight, the adhesion of the treated polyester fiber to rubber decreases, which is not preferable. The above spinning oil can be used in either a hydrous or non-aqueous form, and the solid content concentration in the case of water is 15 to 25.
Weight % is appropriate. The spinning oil has the three components (a) to (c) as essential components, but if the amount is 30 parts by weight or less, it may contain compounds generally called smoothing agents, such as mineral oil and dibasic acid monomers. Alternatively, diesters and fatty acid esters of polyhydric alcohols can be contained. Furthermore, an epoxy compound may be included as long as it does not cause staining of the hot plate, stretching rolls, etc. or generation of smoke during stretching. In addition, additives such as emulsifiers, static electricity generation preventive agents, and extreme pressure property improvers can be added to the above-mentioned spinning oil as long as they do not reduce adhesion.
The proportion of other components is suitably 40 parts by weight or less in the total amount. The treatment with a spinning oil in step A means an operation in which the polyester fiber and the treatment agent come into contact,
This also applies to the following steps B and C. Therefore, the application of the spinning oil in step A is carried out at any stage after melt spinning by immersing the fiber in the spinning oil or by applying the spinning oil to the fibers using a roller or the like. The above step A can be carried out extremely efficiently without yarn breakage or smoke generation during heating and stretching. Moreover, the polyester fiber obtained by adhesion treatment in the subsequent steps B and C is different from the polyester fiber obtained by the same adhesive treatment using a spinning oil other than the spinning oil consisting of components (a) to (c) above. Compared to this, the adhesion to rubber is significantly improved. Next, the B and C steps which are performed on the polyester fibers drawn after the A step will be explained. First, in step B, polyester fibers are treated in a first treatment bath containing an isocyanate compound. Examples of the isocyanate compounds used here include polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, hexamethylene diisocyanate, and triphenylmethane triisocyanate; For example, phenols such as phenol, cresol, and resorcinol; oximes such as caprolactams; acetoxime and methyl ethyl ketone oxime;
- It is a blocked isocyanate prepared by adding alcohols such as -butanol and t-pentanol, and ethyleneimine. This first treatment bath contains an isocyanate compound as an essential component, but may also contain small proportions of rubber latex, epoxy compounds, carbon black, RFL, and the like. The first treatment bath is preferably adjusted to have a concentration of 1 to 30% by weight, particularly 5 to 15% by weight. Next, in step C, the polyester fibers are treated in a second treatment bath using RFL. The RFL used here is a resorcinol/formaldehyde initial condensate obtained from water, resorcinol, formaldehyde, and caustic soda, and this condensate is poured into rubber latex to form a resorcinol/formaldehyde/rubber latex mixture. Note that ammonia may be used as a condensation catalyst instead of the above caustic soda. Examples of the above-mentioned rubber latex include natural rubber latex, styrene-butadiene copolymer rubber latex, chloroprene rubber latex, and styrene-butadiene copolymer rubber latex.
Examples include butadiene-vinylpyridine copolymer rubber latex and nitrile rubber latex. This second treatment bath has RFL as an essential component, but it can also contain small proportions of blocked isocyanate compounds, epoxy compounds, carbon black, etc., and has a solid content of 1 to 30% by weight.
In particular, it is desirable to prepare and use an aqueous solution containing 5 to 20% by weight. In order to apply the first treatment bath in step B and the second treatment bath in step C to the polyester fibers, any method such as immersion in a liquid bath or spraying from a nozzle can be used. The amount of solid content deposited on the polyester fiber is 0.5 to 10.0% by weight, especially 1.0 to 5.0% by weight as the first treatment bath composition.
The weight percent of the second treatment bath composition is suitably in the range of 1.0 to 10.0 weight percent, particularly 2.0 to 6.0 weight percent. Here, if the amount of solid content attached is too small, the adhesion force will decrease, and if it is too large, the solid content will increase and the process passability will be deteriorated, which is not preferable. In order to control the amount of solid content attached to the polyester fibers, means such as squeezing with a pressure roller, blowing with air, and suction may be used. In step B of the present invention, after the polyester fiber is treated with the first treatment bath, it is dried at a temperature of 120 to 250°C, and then heat-treated at a temperature of 160 to 250°C, particularly 180 to 230°C. In the process, after being treated in the second treatment bath, it is desirable to dry at a temperature of 100 to 250°C, and then heat-treat at a temperature of 200 to 260°C, particularly 210 to 250°C. If the heat treatment temperature is too low, the adhesion to the rubber will be insufficient, and if it is too high, the polyester fibers will melt, resulting in a significant decrease in strength, which is not preferred. The polyester fibers thus treated by the method of the present invention have general properties such as excellent tensile strength and dimensional stability for rubber reinforcement, have good moldability and excellent fatigue resistance, and are compoundable. The adhesion between polyester fibers and rubber when subjected to a peel adhesion test after embedding and vulcanizing in rubber was extremely good, and this can be said to be a high level of performance that particularly meets the performance requirements of power transmission belts. The present invention will be further explained below with reference to Examples. Examples 1 to 7 and Comparative Examples 1 to 7 A polyethylene phthalate filament yarn of 1500 denier and 288 filaments was melt-spun by a conventional method, and the spinning oil shown in Table 1 was applied thereto using an oiling roller, and then the yarn was heated at 250°C. The film was stretched using a hot roller at a stretching ratio of 5.5 times, and the stretchability at this time was evaluated. The amount of oil applied to the obtained yarn was 0.9% by weight. The stretchability was evaluated by the number of thread breakages that occurred during stretching of polyethylene terephthalate filament equivalent to 1 ton of fiber. Next, from the above polyethylene terephthalate filament yarn, 15002/3, number of first twists 30T/10cm,
An untreated cord with a twist count of 20 T/cm was obtained, and it was treated with an isocyanate compound (“Millionate MR200” manufactured by Nippon Polyurethane Co., Ltd.) and toluene (Reagent Grade 1, manufactured by Katayama Chemical Industry Co., Ltd.) at a ratio of 10/90 by weight. Pass through the formulated first treatment bath dipping liquid,
Then, after drying, it was heat-treated at 220°C. Meanwhile, 293g of water, 13g of resorcinol, 14g of formalin
g and 1.3 g of caustic soda and aged for about 2 hours while stirring, then 182 g of neoprene rubber latex (“Neoprene 650” manufactured by Showa Neoprene Co., Ltd.) was blended, stirred uniformly, and aged for another 24 hours. The second treatment bath was thus prepared. Next, pass the above-mentioned first processing bath processing cord through this second processing bath, and after drying
A treated cord was obtained by heat treatment at 230°C. The treatment cord thus obtained has a solid content of 5.0% by weight in the first treatment bath and 6.0% by weight in the second treatment bath.
Each was attached to the fibers. Next, the above-mentioned treated cord was embedded in chloroprene rubber, and the reinforced rubber material obtained by heating and vulcanizing at 150°C for 30 minutes was subjected to the CRA method (using a tensilon to apply force to peel off the treated cord embedded in the rubber from the rubber). The adhesion was evaluated by (measurement).
The results are also shown in Table-1.

【table】

[Table] As is clear from the results in Table 1, the rubber reinforcing polyester fiber obtained by the method of the present invention has significantly improved adhesion to rubber, and has performance suitable for power transmission belt applications. are doing. On the other hand, when silicone oil is not added, there are many thread breakages during stretching (Comparative Example 2), and when too much silicone oil is added to cover the stretchability, the adhesion to the rubber decreases (Comparative Example 3). ). Moreover, (a)
Also, when using other common emulsifiers as component (b), the adhesion cannot be improved (Comparative Examples 4 and 6). Examples 8 to 12 and Comparative Examples 8 to 10 A polyethylene terephthalate filament yarn of 1000 denier and 192 filaments was melt-spun in a conventional manner, and after applying the spinning oil shown in Table 2 using an oiling roller, the yarn was heated at 220°C. The film was stretched using a hot roller at a stretching ratio of 5.4 times.
The amount of oil applied to the obtained yarn was 0.7% by weight. In the following, the first treatment bath and the second treatment bath were applied in the same manner as in Examples 1 to 7, and the adhesiveness of the obtained treated cords to rubber was evaluated. These results are also shown in Table-2. As is clear from the results in Table 2, in the method of the present invention, even when the spinning oil contains other components within an acceptable range, treated cords with a high degree of adhesiveness that can be used for power transmission belts can be obtained. . On the other hand, when a normal smoothing agent is used in an amount as large as that contained in a general spinning oil (Comparative Examples 8 to 10), the adhesion to rubber is undesirable.

【table】

【table】

Claims (1)

[Claims] 1 The polyester fiber is A. (a) at least one selected from ethylene oxide and/or propylene oxide adducts of aliphatic amines having 8 to 22 carbon atoms, (b) polyhydric alcohols and ethylene oxide and/or propylene adducts of polyhydric alcohols; at least one selected from oxide adducts and (c)
Contains dimethylpolysiloxane, 40 to 80 parts by weight of (a) and 10 to 10 parts by weight of (b) in 100 parts by weight of (a), (b), and (c).
After treatment with a spinning oil containing 50 parts by weight and (c) in a proportion of 0.5 to 10 parts by weight, B. treatment with a treatment bath containing an isocyanate compound, and then C. a resorcinol-formaldehyde-rubber latex mixture. A method for producing polyester fibers for rubber reinforcement, which is characterized by treatment in a treatment bath.