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CN-122013511-A - First bath dipping liquid for two-bath dipping method of fiber framework material

CN122013511ACN 122013511 ACN122013511 ACN 122013511ACN-122013511-A

Abstract

The invention belongs to the technical field of dipping solutions, and particularly relates to a first bath dipping solution for a two-bath dipping method of fiber framework materials. The invention adds active sulfur-containing compound into the first bath gum dipping liquid of the two-bath gum dipping method for the first time to form a polysulfide bond-K-R structure, which is equivalent to providing definite chemical crosslinking between the first bath gum dipping liquid and the second bath/rubber, realizing the improvement of the stripping force and better improving the adhesive property and the oversulfur decay property of gum dipping. Under the condition of ensuring the initial gum dipping and the over-sulfur adhesive force, the active sulfur-containing compound can obviously reduce the addition amount of two main components of the epoxy compound and the blocked isocyanate in the first bath gum dipping liquid, the solid content can be reduced from more than 3.00% to 2.30-2.80% in the conventional process, and the raw material cost is obviously saved on the basis of improving the adhesive property of the gum dipping.

Inventors

  • JIN JIYANG
  • ZHAO CHENXIA
  • SHI RUI
  • WU JING
  • WANG RUFA
  • ZHU WENXIANG

Assignees

  • 浙江海利得科技有限公司
  • 浙江海利得新材料股份有限公司
  • 海利得新材料研究(上海)有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. A first bath dipping liquid for a two-bath dipping method of fiber framework materials is characterized in that, The first bath dipping liquid takes water as a solvent and comprises an epoxy compound, a blocked isocyanate compound and an active sulfur-containing compound, wherein the solid content of the first bath dipping liquid is 1.00-5.00%, the weight of the active sulfur-containing compound is 0.50-5.00% of the dry weight of the first bath dipping liquid, and the dry weight of the first bath dipping liquid comprises, by weight: 55-80 parts of blocked isocyanate compound, 15-40 parts of epoxy compound and 0.05-10 parts of active sulfur-containing compound.
  2. 2. The first bath gum dipping solution for the two-bath gum dipping method of fiber skeleton materials according to claim 1, wherein the solid content of the first bath gum dipping solution is 2.30-2.80%.
  3. 3. The first bath tub for a two-bath tub process for a fibrous web material according to claim 1, wherein the weight of the active sulfur-containing compound is 1.00 to 3.00% of the dry weight of the first bath tub.
  4. 4. A first bath dip for a two bath dip process for a fibrous framework material according to claim 1, wherein the reactive sulfur-containing compound comprises disulfide, trisulfide or tetrasulfide bonds and comprises at least one second functional group which is any one or a combination of two of siloxane groups, silicon alkoxides groups, carboxyl groups, hydroxyl groups, amino groups, epoxy groups.
  5. 5. A first bath gum for a two bath gum dipping process for fiber web materials according to claim 1 or 4 wherein the structural formula of said active sulfur-containing compound is as shown in formula I: ; A general formula I; wherein a is an integer of 1 to 3, p and q are each independently integers of 0 to 3, and p and q are not both 0; K 1 and K 2 are each independently a combination of any one or more of an unsubstituted or branched substituted C 1 ~C 10 alkyl chain, C 1 ~C 10 alkenyl chain, C 1 ~C 10 alkynyl chain, C 1 ~C 10 heterochain, C 3 ~C 10 cycloalkyl chain, C 2 ~C 10 cyclic heterochain, C 3 ~C 10 cyclic double bond-containing chain, C 3 ~C 10 cyclic triple bond-containing chain, phenyl, naphthyl, heterocyclyl; the hetero chain is a carbon chain containing any one or a combination of more of oxygen, nitrogen and sulfur atoms; The heterocyclic group is any one or a combination of more of pyridine, thiophene and furan; the branched chain comprises any one or a combination of a plurality of alkyl chains, alkenyl chains, alkynyl chains, hetero chains, cycloalkyl chains, cyclic hetero chains, cyclic double bond-containing chains, cyclic triple bond-containing chains, phenyl groups, naphthyl groups and heterocyclic groups; R 1 and R 2 are each independently a combination of any one or more of C 3 ~C 12 alkoxy silicon groups, carboxyl groups, hydroxyl groups, amino groups or epoxy groups.
  6. 6. The first bath gum for two-bath gumming process of claim 5, wherein when R 1 or R 2 is trialkoxysilyl or dialkoxymethylsilyl, the number of carbon atoms of K 1 or K 2 is not more than 4; When R 1 or R 2 is epoxy, the total number of carbon atoms of K 1 or K 2 is not more than 3; when R 1 or R 2 is carboxyl, the total number of carbon atoms of K 1 or K 2 is not more than 6 times the number of carbon atoms in the carboxyl; When R 1 or R 2 is amino, the total number of carbon atoms of K 1 or K 2 is not more than 4 times the number of amino groups; When R 1 or R 2 is hydroxyl, the total number of carbon atoms of K 1 or K 2 is not more than 4 times the number of oxygen atoms.
  7. 7. A first bath dip for a two bath dip process for a fibrous skeletal material according to claim 5, wherein in formula I a = 1, p = 1 or 2, q = 1 or 2,K 1 or K 2 are each independently alkylene of C 1 ~C 3 .
  8. 8. A first bath dip for a two bath process for the impregnation of fibrous framework materials according to claim 1 or 4, wherein the active sulphur-containing compound is any one or more of cystamine dihydrochloride, 3-dithiodipropionic acid, bis [3- (triethoxysilyl) propyl ] -disulphide, bis (2-epoxypropyl) disulphide, bis (3-hydroxypropyl) disulphide, bis [3- (triethoxysilyl) propyl ] -tetrasulphide, cystine, bis (2, 3-dihydroxypropyl) disulphide.
  9. 9. A first bath dip for a two bath dip process for a fibrous web material according to claim 1, wherein the epoxy compound comprises at least one epoxy monomer having at least one epoxy group, the epoxy monomer being a water soluble or water dispersible compound.
  10. 10. A first bath dip for a two bath dip process for a fibrous skeletal material according to claim 1, wherein the blocked isocyanate-based compound is an isocyanate protected by a blocking agent; the blocking agent comprises alcohol, phenol, beta-dicarbonyl compound, oxime compound and/or amide compound; The isocyanate is any one or a combination of more of diphenylmethane-4, 4 '-diisocyanate, toluene diisocyanate, polymethylene polyphenyl polyisocyanate, 4' -dicyclohexylmethane diisocyanate, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate and paraphenylene diisocyanate.

Description

First bath dipping liquid for two-bath dipping method of fiber framework material Technical Field The invention belongs to the technical field of dipping solutions, and particularly relates to a first bath dipping solution for a two-bath dipping method of fiber framework materials. Background The fiber skeleton material is used as a key reinforcing component in rubber products, is widely applied to the industrial fields of tires, conveyor belts, rubber tubes and the like, and has the core functions of bearing mechanical load and maintaining the dimensional stability of the products. In practical application, the interface bonding strength between the framework material and the rubber matrix directly determines the durability and safety of the product, and particularly, for high polymer fibers such as polyester, nylon and the like, the surface polarity is low, the chemical inertia is strong, and the high polymer fibers are difficult to form firm combination with rubber, so that the high polymer fibers are difficult to be a technical attack point of the industry. Traditionally, resorcinol-formaldehyde-latex (RFL) impregnation systems have been commonly used in the industry to treat fiber surfaces to achieve adhesion through the physical action of phenolic resins with the fibers and the co-vulcanization of the latex with the rubber. However, the RFL system has the remarkable limitations that resorcinol and formaldehyde are toxic substances, which not only threaten the health of production personnel, but also face application restrictions along with tightening of environmental regulations, and on the other hand, the adhesion effect of a single RFL system is insufficient for materials such as polyester, and the like, namely, a two-bath dipping method is adopted, namely, a first bath pretreatment is carried out through an epoxy-isocyanate system, and then a second bath of RFL is applied. The two-bath gumming method adopts a multi-step process, which can improve the adhesive force, but increases the energy consumption, the equipment complexity and the production cost, and weakens the cost advantage of the polyester material. In order to avoid the environmental protection problem of phenolic aldehyde system, the inventor of the invention discloses a non-phenolic aldehyde environmental protection dipping solution of fiber framework material in the patent with the application number 202211156718.0, which can improve the action strength between the dipping adhesive resin and latex and between the dipping adhesive resin and rubber, and achieve the effect of improving the integral adhesive force, but is limited by the cost and does not realize the industrialized application. Therefore, two-bath impregnation is still the main stream of industrial applications, and it is critical whether the adhesive retention (resistance to decay of over-sulfur) in the later stage of vulcanization (i.e., the over-sulfur condition) of rubber products can be improved. In contrast, the inventors of the present invention have found that when a sulfur-containing compound is added to a second bath dip of one bath or two bath, it can chemically bond with a phenolic adhesive resin and also chemically bond with rubber and latex by sulfur bonds, thereby effectively improving the strength of action between the dip and rubber. However, the sulfur-containing compound is up to 20% by dry weight, and thus, if such a high content of sulfur-containing compound is added to the two-bath first bath dope, there are certain problems that (1) part of the groups (e.g., hydroxyl groups) of the sulfur-containing compound react with the terminal groups on the surface of the polyester in a competitive manner, resulting in insufficient activation of the surface of the polyester, and (2) the higher addition of the sulfur-containing compound may cause excessive crosslinking between the rubber and the dope, and the rubber itself may cause hardening, embrittlement and decrease in flexibility of the adhesive interface layer. In the dynamic fatigue or bending process, the embrittled interface is more likely to generate microcracks, so that the adhesive force is attenuated prematurely, even interfacial brittle stripping occurs, and (3) the production cost is increased. It should be further noted that while the first bath solids content of the two-bath process is typically not high (typically below 6.50%, the lowest about 3.00%, but the performance decreases with decreasing solids content, thus the cost reduction by decreasing solids content is a significant lower bottleneck in the actual production), the epoxy monomers and blocked isocyanate monomers used tend to involve elaborate purification and water-dispersion pretreatment and are therefore also costly, and the reduction in their amount may in turn cause a cliff drop in adhesive properties. Thus, in conventional RFL two bath formulations, lowering the first bath solids content not only results in a decrease in cord adh