阅读说明：本技术 芳纶纤维硬线绳浸胶前处理液和芳纶纤维硬线绳浸胶方法 (Pretreatment liquid for dipping aramid fiber hard cord and dipping method of aramid fiber hard cord ) 是由 于冲 于得江 姜伟 于 2020-12-30 设计创作，主要内容包括：本发明提供了一种芳纶纤维硬线绳浸胶前处理液,包括以下重量份的组分：异氰酸酯1～20份,固化增强剂1～30份,甲苯100～200份。在本发明中,前处理液中的固化增强剂会在浸胶芳纶硬线绳表面形成渗透性强、交联固化程度高的胶膜,不仅可极大增强芳纶纤维之间的抱合性,减轻切割起毛的现象,还能提高胶膜韧性,增强胶膜耐磨性,减轻打磨起毛的现象。同时,固化增强剂还可弥补异氰酸酯对芳纶纤维造成破坏形成的“烧蚀空洞”,在一定程度上修复浸渍液对芳纶纤维的破坏,保证芳纶硬线绳可以在增强固化程度的前提下,仍然保持较高的断裂强力。(The invention provides a pretreatment liquid for gum dipping of an aramid fiber hard cord, which comprises the following components in parts by weight: 1-20 parts of isocyanate, 1-30 parts of curing reinforcing agent and 100-200 parts of methylbenzene. In the invention, the curing reinforcing agent in the pretreatment liquid can form a glue film with strong permeability and high crosslinking curing degree on the surface of the dipped aramid hard cord, so that the cohesion between aramid fibers can be greatly enhanced, the cutting fluffing phenomenon can be reduced, the toughness of the glue film can be improved, the wear resistance of the glue film can be enhanced, and the polishing fluffing phenomenon can be reduced. Meanwhile, the curing reinforcing agent can also make up an 'ablation cavity' formed by the damage of isocyanate to aramid fibers, repair the damage of the impregnating solution to the aramid fibers to a certain extent, and ensure that the aramid hard cord can still maintain higher breaking strength on the premise of reinforcing the curing degree.)

1. The pretreatment liquid for gum dipping of the aramid fiber hard cord comprises the following components in parts by weight:

1-20 parts of isocyanate, 1-30 parts of curing reinforcing agent and 100-200 parts of methylbenzene.

2. The pre-dip treatment solution according to claim 1, wherein the curing enhancer comprises one or more of an acrylic polymer, a polyoxyethylene-based compound, a maleic anhydride polymer, and an epoxy vinyl compound.

3. The pretreatment solution for gum dipping according to claim 2, wherein the polyoxyethylene-based compound comprises polyoxyethylene glycidyl ether and/or dodecyl polyoxyethylene ether.

4. The pre-dip treatment solution according to claim 2, wherein the epoxy vinyl compound comprises an epoxy vinyl phenol resin and/or a bisphenol a epoxy vinyl resin.

5. The pretreatment solution for dipping glue according to any one of claims 1 to 4, wherein the mass ratio of the isocyanate to the curing enhancer is 1 (1 to 5).

6. The preparation method of the pretreatment liquid for gum dipping of the aramid fiber hard cord comprises the following steps:

adding isocyanate into toluene until the isocyanate is completely dissolved to obtain an isocyanate toluene solution;

and adding the curing reinforcing agent into the isocyanate toluene solution until the solid reinforcing agent is completely dissolved to obtain the pre-dipping treatment solution.

7. The pretreatment method for dipping the aramid fiber hard cord comprises the following steps:

providing twisted aramid fibers;

dipping the twisted aramid fiber in the pretreatment liquid for dipping or the pretreatment liquid for dipping obtained by the preparation method of claim 6, according to any one of claims 1 to 5;

and drying the impregnated twisted aramid fiber.

8. The pretreatment method for pretreatment before dipping according to claim 7, wherein the drying temperature is 220 ℃ to 260 ℃.

9. The gum dipping method of the aramid fiber hard cord comprises the following steps:

obtaining pretreated aramid fibers by the pretreatment method for dipping in glue according to claim 7 or 8;

dipping the pretreated aramid fiber in RFL dipping solution;

and carrying out secondary drying on the impregnated aramid fiber to obtain the aramid fiber hard cord.

10. The impregnation method according to claim 9, wherein the temperature of the second drying is 220 ℃ to 260 ℃.

Technical Field

The invention relates to the technical field of rubber conveyor belts, in particular to a pretreatment liquid for gumming an aramid fiber hard cord and a gumming method of the aramid fiber hard cord.

Background

The aramid fiber has the characteristics of small density, large elastic modulus, high strength, small elongation, high temperature resistance, wear resistance, impact resistance and the like, and is a novel framework material for rubber products such as adhesive tape rubber tubes and the like. The gum dipping aramid hard cord can improve the strength and durability of rubber conveyor belts mainly comprising V belts and V-ribbed belts and other rubber products. The gum dipping film formed by the rubber treatment agent in the gum dipping aramid cord not only improves the adhesiveness between rubber substrates, but also protects the aramid protofilament, thereby improving the durability of rubber products.

However, because the surface active groups of the aramid fibers are few, the aramid fibers are difficult to be crosslinked with impregnating materials, so that the impregnation of the aramid fibers has a plurality of problems. Especially in the cutting belt processing process using aramid hard cord as framework material, the problem of cutting fuzzing exists, and the fuzzing phenomenon is further aggravated because a part of belt processing also has a grinding process.

In order to reduce fluffing in the prior art, the aramid fiber is generally activated by adopting isocyanate, and the curing degree of the aramid fiber is improved by increasing the using amount of the isocyanate. But after the usage amount of the isocyanate is increased, the overall strength of the gum dipping aramid hard cord is greatly reduced,

disclosure of Invention

The invention aims to provide a pretreatment liquid for gumming an aramid fiber hard cord and a gumming method for the aramid fiber hard cord, which reduce the influence of cutting fuzzing on the premise of ensuring the strength of the aramid fiber hard cord.

The invention provides a pretreatment liquid for gum dipping of an aramid fiber hard cord, which comprises the following components in parts by weight:

1-20 parts of isocyanate, 1-30 parts of curing reinforcing agent and 100-200 parts of methylbenzene.

Preferably, the curing enhancer includes one or more of an acrylic polymer, a polyoxyethylene compound, a maleic anhydride polymer, and an epoxy vinyl compound.

Preferably, the polyoxyethylene-based compound comprises polyoxyethylene glycidyl ether and/or dodecyl polyoxyethylene ether.

Preferably, the epoxy vinyl compound comprises an epoxy vinyl phenol formaldehyde resin and/or a bisphenol a epoxy vinyl resin.

Preferably, the mass ratio of the isocyanate to the curing reinforcing agent is 1 (1-5).

The invention provides a preparation method of a pretreatment solution for gum dipping of an aramid fiber hard cord in the technical scheme, which comprises the following steps:

adding isocyanate into toluene until the isocyanate is completely dissolved to obtain an isocyanate toluene solution;

and adding the curing reinforcing agent into the isocyanate toluene solution until the solid reinforcing agent is completely dissolved to obtain the pre-dipping treatment solution.

The invention provides a pretreatment method for gumming aramid fiber hard cord, which comprises the following steps:

providing twisted aramid fibers;

dipping the twisted aramid fiber in the pretreatment liquid for dipping or the pretreatment liquid for dipping obtained by the preparation method in the technical scheme;

and drying the impregnated twisted aramid fiber.

Preferably, the drying temperature is 220-260 ℃.

The invention also provides a gum dipping method for the aramid fiber hard cord, which comprises the following steps:

obtaining pretreated aramid fibers by adopting the impregnation pretreatment method in the technical scheme;

dipping the pretreated aramid fiber in RFL dipping solution;

and carrying out secondary drying on the impregnated aramid fiber to obtain the aramid fiber hard cord.

Preferably, the temperature of the second drying is 220-260 ℃.

The invention provides a pretreatment liquid for gum dipping of an aramid fiber hard cord, which comprises the following components in parts by weight: 1-20 parts of isocyanate, 1-30 parts of curing reinforcing agent and 100-200 parts of methylbenzene. In the invention, the curing reinforcing agent in the pretreatment liquid can form a glue film with strong permeability and high crosslinking curing degree on the surface of the dipped aramid hard cord, so that the cohesion between aramid fibers can be greatly enhanced, the cutting fluffing phenomenon can be reduced, the toughness of the glue film can be improved, the wear resistance of the glue film can be enhanced, and the polishing fluffing phenomenon can be reduced. Meanwhile, the curing reinforcing agent can also be connected with a molecular chain which is damaged and broken in the activation process, so that an 'ablation cavity' formed by damage of isocyanate to aramid fibers is compensated, damage of the impregnating solution to the aramid fibers is repaired to a certain extent, and the aramid hard-line rope can still keep high breaking strength on the premise of reinforcing the curing degree.

Detailed Description

The invention provides a pretreatment liquid for gum dipping of an aramid fiber hard cord, which comprises the following components in parts by weight:

1-20 parts of isocyanate, 1-30 parts of curing reinforcing agent and 100-200 parts of methylbenzene.

The pre-dipping treatment solution provided by the invention comprises 1-20 parts of isocyanate, preferably 5-15 parts, and more preferably 8-12 parts. In the present invention, the mass concentration of the isocyanate in the pretreatment liquid is preferably 2 to 20%, more preferably 5 to 15%, and most preferably 6.78 to 10%. The pretreatment liquid provided by the invention can improve the curing degree of the aramid fiber on the premise of low isocyanate content, thereby reducing the occurrence of fuzzing and ensuring the overall strength of the aramid fiber hard cord.

The pre-dipping treatment solution provided by the invention comprises 1-30 parts of a curing reinforcing agent, preferably 5-25 parts, and more preferably 10-20 parts. In the present invention, the mass ratio of the isocyanate to the curing enhancer is preferably 1 (1-5), and more preferably 1 (1.25-2). In the present invention, the curing enhancer preferably includes one or more of an acrylic polymer, a polyoxyethylene compound, a maleic anhydride polymer, and an epoxy vinyl compound, and in an embodiment of the present invention, the curing enhancer may be one of an acrylic polymer, a polyoxyethylene compound, a maleic anhydride polymer, and an epoxy vinyl compound, and may also include two, three, or four of an acrylic polymer, a polyoxyethylene compound, a maleic anhydride polymer, and an epoxy vinyl compound. In the present invention, the two embodiments preferably include an epoxy vinyl compound and an acrylic polymer, and the mass ratio of the epoxy vinyl compound to the acrylic polymer is preferably 2: 1; the three schemes preferably comprise an epoxy vinyl compound, an acrylic acid polymer and a polyoxyethylene compound, wherein the mass ratio of the epoxy vinyl compound to the acrylic acid polymer to the polyoxyethylene compound is preferably 10:8: 5; when the curing enhancer is the four embodiment, the mass ratio of the acrylic polymer, the polyoxyethylene compound, the maleic anhydride polymer and the epoxy vinyl compound is preferably 1:1:1: 2.

In the present invention, the polyoxyethylene-based compound preferably includes polyoxyethylene glycidyl ether and/or dodecyl polyoxyethylene ether; the epoxy vinyl compound preferably comprises an epoxy vinyl novolac resin and/or a bisphenol a epoxy vinyl resin.

The pretreatment solution for gum dipping provided by the invention comprises 100-200 parts of toluene, and in the embodiment of the invention, the relative amount of the toluene can be 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts or 200 parts.

The invention provides a preparation method of the impregnation pretreatment liquid in the technical scheme, which comprises the following steps:

adding isocyanate into toluene until the isocyanate is completely dissolved to obtain an isocyanate toluene solution;

and adding the curing reinforcing agent into the isocyanate toluene solution until the solid reinforcing agent is completely dissolved to obtain the pre-dipping treatment solution.

The apparatus used in the preparation of the present invention is not particularly limited, and a vessel known to those skilled in the art, such as a reaction vessel, may be used. In an embodiment of the present invention, the preparation method may specifically be: adding toluene into a reaction kettle, adding isocyanate under the condition of stirring, stirring until the isocyanate is completely dissolved, and then adding a curing reinforcing agent until the isocyanate is completely dissolved to obtain a pre-dipping treatment solution. The stirring conditions in the present invention are not particularly limited, and the stirring technique known to those skilled in the art may be employed.

The invention also provides a pre-treatment method for gumming aramid fiber hard cord, which comprises the following steps:

providing twisted aramid fibers;

dipping the twisted aramid fiber in the pretreatment liquid for dipping or the pretreatment liquid for dipping obtained by the preparation method in the technical scheme;

and drying the impregnated twisted aramid fiber.

The invention has no special limitation on the physical parameters of the aramid fiber, and the aramid fiber for the gum dipping aramid hard cord which is well known by the technical personnel in the field can be adopted. In the invention, the aramid fiber is subjected to gum dipping pretreatment after being subjected to primary twisting and secondary twisting, and the technical scheme of the primary twisting and the secondary twisting is not particularly limited, and can be obtained by adopting the technical scheme of the primary twisting and the secondary twisting which is well known by the technical personnel in the field.

The twisted aramid fiber is dipped in the dipping pretreatment solution of the technical scheme. In the present invention, the weight of the pretreatment liquid is preferably 50% of the weight of the aramid fiber; the temperature of the impregnation is preferably 25 ℃; the time for the immersion is preferably 3 seconds. In the embodiment of the present invention, it is preferable that the twisted aramid fiber is passed through an impregnation tank filled with the pretreatment liquid at a speed of 35 m/min.

After dipping the pretreatment liquid, the aramid fiber obtained by the dipping pretreatment liquid is dried. In the invention, the drying temperature is 220-260 ℃, more preferably 240-250 ℃; the drying time is preferably 90 seconds. In the embodiment of the present invention, it is preferable that the twisted aramid fiber passed through the pretreatment liquid is rapidly passed through the oven.

The invention also provides a gum dipping method for the aramid fiber hard cord, which comprises the following steps:

obtaining pretreated aramid fibers by adopting the impregnation pretreatment method in the technical scheme;

dipping the pretreated aramid fiber in RFL dipping solution;

and carrying out secondary drying on the impregnated aramid fiber.

After the pretreatment aramid fiber is obtained by adopting the pretreatment method in the technical scheme, the pretreatment aramid fiber is dipped in RFL dipping solution. In the invention, the RFL dipping solution is prepared by taking ammonia water as a catalyst, firstly reacting resorcinol with formaldehyde to obtain m-methyl resin solution with a certain condensation degree, and then mixing the m-methyl resin solution with latex to react to prepare emulsion with a certain concentration;

the RFL (resorcinol-formaldehyde-latex) dipping solution preferably comprises the following components in parts by weight:

1-20 parts of pH value regulator, 10-80 parts of softened water, 60-120 parts of latex and 3-20 parts of resorcinol and formaldehyde water-soluble condensate (RF condensate).

In the present invention, the weight part 1 of each component in the pretreatment liquid and the weight part 1 of each component in the RFL dip are set independently, and may be the same or different.

In the invention, the RFL dipping solution preferably comprises 1-20 parts of pH value regulator, more preferably 5-15 parts, and most preferably 8-12 parts. In the present invention, the pH adjuster preferably includes one or both of ammonia water and a sodium hydroxide solution; the mass concentration of the ammonia water is preferably 23-25%; the mass concentration of the sodium hydroxide solution is preferably 5%. In the invention, the pH value of the RFL dipping solution is preferably 10-11 due to the addition of the pH value regulator.

In the invention, the RFL dipping solution preferably comprises 10-80 parts of softened water, more preferably 20-70 parts, and most preferably 30-60 parts;

in the invention, the RFL dipping solution preferably comprises 60-120 parts of latex, more preferably 70-110 parts, and most preferably 80-100 parts; the latex is preferably one or more of butadiene-pyridine latex, butadiene-styrene latex, chloroprene latex, chlorosulfonated polyethylene latex, butyronitrile latex and acrylic acid and maleic anhydride modified derivatives of the latex; in the present invention, the solid content of the latex is preferably 40%.

In the invention, the RFL dipping solution preferably comprises 3-20 parts of a water-soluble condensation compound of resorcinol and formaldehyde, more preferably 5-15 parts, and most preferably 8-12 parts;

in the present invention, the preparation method of the RFL dipping solution preferably includes the following steps:

and stirring and mixing the latex, the RF condensation compound, the pH value regulator and softened water at normal temperature to obtain the RFL dipping solution.

In the present invention, the solution A and the solution B are preferably incubated at 25 ℃ for use.

In the invention, the mass ratio of the pretreated aramid fiber to the RFL dipping solution is preferably 2: 1; the dipping temperature is preferably 25 ℃; the time for the impregnation is preferably 3 s. In the embodiment of the present invention, it is preferable that the pretreated aramid fiber is passed through an impregnation tank filled with the RFL dip solution at a speed of 35 m/min.

After the gum dipping, the obtained gum dipping aramid fiber is dried. For the sake of clear distinction, the drying of the gum-dipped aramid fiber is named as second drying, and the temperature of the second drying is preferably 220-260 ℃, and more preferably 230-250 ℃; the time of the second drying is preferably 90 s. In the embodiment of the present invention, it is preferable that the dipped aramid fiber obtained by dipping is quickly passed through an oven for secondary drying.

The pretreatment solution for dipping the aramid fiber hard cord and the method for dipping the aramid fiber hard cord provided by the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.

Example 1

Adding 100 parts of toluene into a reaction kettle, stirring at normal temperature, adding 8 parts of isocyanate until the isocyanate is completely dissolved, adding 10 parts of acrylic polymer, and stirring at normal temperature until the acrylic polymer is completely dissolved to obtain a pretreatment solution;

stirring and mixing 80 parts of butadiene-pyridine latex with the concentration of 40 wt%, 10 parts of RF condensation compound, 13 parts of ammonia water with the concentration of 23 wt% and 36 parts of softened water at normal temperature to obtain an RFL treatment solution with the pH value of 10;

the aramid fiber after the first twisting and the second twisting passes through a dipping tank filled with pretreatment liquid at the speed of 35 m/min, and is quickly dried for 90s by an oven at the temperature of 130 ℃; and then dipping the RFL cord in a dipping tank filled with the RFL treatment solution at the speed of 35 m/min, and quickly drying the RFL cord in an oven at the temperature of 240 ℃ to dry and cure the RFL treatment agent to obtain the dipped aramid hard cord.

Example 2

The dipped aramid hard cord was prepared according to the protocol of example 1, except that the pretreatment solution was replaced with the protocol of the following composition:

8 parts of isocyanate, 10 parts of polyoxyethylene glycidyl ether and 120 parts of toluene.

Example 3

The dipped aramid hard cord was prepared according to the protocol of example 1, except that the pretreatment solution was replaced with the protocol of the following composition:

8 parts of isocyanate, 10 parts of epoxy vinyl phenolic resin, 5 parts of acrylic polymer and 150 parts of toluene.

Example 4

The dipped aramid hard cord was prepared according to the protocol of example 1, except that the pretreatment solution was replaced with the protocol of the following composition:

9 parts of isocyanate, 10 parts of bisphenol A epoxy vinyl resin, 8 parts of acrylic polymer, 5 parts of dodecyl polyoxyethylene ether and 180 parts of toluene.

Example 5

The dipped aramid hard cord was prepared according to the protocol of example 1, except that the pretreatment solution was replaced with the protocol of the following composition:

7 parts of isocyanate, 10 parts of epoxy vinyl phenolic resin, 5 parts of acrylic polymer, 5 parts of polyoxyethylene glycidyl ether, 5 parts of maleic anhydride polymer and 180 parts of toluene.

Tensile property tests are carried out on the dipped aramid hard cord obtained in the embodiments 1 to 5 and the conventional products in the market according to the test method of the tensile property of the GBT30311-2013 dipped aramid yarn, cord and cord, and the results are shown in the table 1, wherein the table 1 is the performance test results of the dipped aramid cord obtained in the embodiments 1 to 5 in the invention and the conventional products in the market.

Table 1 performance test results of the dipped aramid cords and the conventional products on the market obtained in examples 1 to 6 of the present invention

As can be seen from table 1, the gum-dipped aramid hard cord prepared by the invention has good cutting and polishing effects on the premise of maintaining high strength, and especially in the scheme of the embodiment 1, when an acrylic polymer is used as a curing reinforcing agent, each index is at the best level.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.