1. The preparation method of the gum dipping cord fabric for the radial tire for passenger is characterized by comprising the following steps:

(1) solid-phase polymerization:

taking a polyester wet slice as a raw material, heating to fully activate low molecular terminal hydroxyl and carboxyl of polyester, so that chain growth reaction occurs between low molecular chains step by step, and the viscosity of the produced high-viscosity PET slice reaches more than 1.19 dl/g;

(2) a spinning process:

melting process: high viscosity PET chip in N₂Under protection, heating and melting the raw materials within the range of 280-300 ℃, and then feeding the raw materials into a spinning manifold, wherein the temperature of the spinning manifold is controlled at 280-300 ℃; producing high-strength protofilaments;

(3) twisting process

Twisting the produced high-strength precursor on a direct twisting machine at the ingot speed of 8500-9000 r/min, carrying out outward expansion of 10-20%, carrying out inward expansion of 2.5-4.5 in the range of 1-10 and carrying out overfeed ratio of-2.0-1.5%;

(4) weaving process

Weaving the twisted compound twisted yarn on an air jet loom at the speed of 550-750 revolutions per minute;

(5) impregnation step

The conditions of one bath dipping are as follows: the dipping solution mainly comprises closed isocyanate and epoxy resin, the solid content is 3.8%, the drying temperature is 155-165 ℃, and the tension is 1000-1500 daN; the drafting temperature is 235-245 ℃, and the tension is 2000-3500 DAN; the speed is 75-85 m/min.

The conditions of the two-bath impregnation treatment are as follows: the two-bath impregnation liquid takes RFL as a main body, the solid content is 24.1%, the drying temperature is 155-165 ℃, and the tension is 1000-1500 daN; setting temperature is 235-245 ℃, and tension is 900-1100 daN; the speed is 75-85 m/min;

finally obtaining the fine denier high strength 930dtex/2 gum dipping cord fabric used for passenger radial tires.

2. The method of claim 1, wherein a temperature > 210 ℃ and an air volume > 6800m are employed during the solid phase polymerization process³The process conditions of/h are sufficient to activate the low molecular terminal hydroxyl groups and carboxyl groups of the polyester.

3. The method of claim 1, wherein the spinning step comprises ultra-low melt extrusion by a screw extruder, melt distribution, metering pump, spinning assembly, cooling and forming, oiling, stretch-setting, relaxation, meshing, and winding to produce high-strength filaments.

4. The method of claim 1, wherein in the dipping step, a dipping process is performed at a high-temperature draft zone temperature of 235 to 245 ℃ and a draft tension of > 2000daN, and a preferable range of the draft/retraction ratio is adjusted to 2.0 to 2.5%.

Background

With the urgent need of the tire industry for high-performance cord fabric, more and more tire enterprises begin to pay attention to the framework material products with light weight, small rolling resistance and good heat resistance. At present, the semi-steel radial tire body is made of polyester or nylon materials. For a general performance tire, nylon has disadvantages in dimensional stability and cost performance. In addition, it is very critical for tire enterprises to reduce the use cost of raw materials. Therefore, the development of fine-denier high-strength impregnated cord fabrics is receiving the attention of the market. The cord fabric can be used for replacing common cord fabric products, has the similar strength level as the common cord fabric, can achieve better size stability, can just meet the requirements of light weight and low rolling resistance of rubber framework materials, and becomes an ideal material for replacing common PET and the like.

Disclosure of Invention

The invention aims to provide a preparation method of 930dtex/2 dipped cord fabric for passenger radial tires, the product strength is more than or equal to 140N, and the dimensional stability is as follows: 5.8 +/-0.5%, and the product has high strength and high size stability.

The invention is realized by the following technical scheme:

the preparation method of the gum dipping cord fabric for the radial tire for passenger is characterized by comprising the following steps:

(1) solid-phase polymerization:

taking a polyester wet slice as a raw material, heating to fully activate low molecular terminal hydroxyl and carboxyl of polyester, so that chain growth reaction occurs between low molecular chains step by step, and the viscosity of the produced high-viscosity PET slice reaches more than 1.19 dl/g;

(2) a spinning process:

meltingThe process is as follows: high viscosity PET chip in N₂Under protection, heating and melting the raw materials within the range of 280-300 ℃, and then feeding the raw materials into a spinning manifold, wherein the temperature of the spinning manifold is controlled at 280-300 ℃; producing high-strength protofilaments;

(3) twisting process

Twisting the produced high-strength precursor on a direct twisting machine at the ingot speed of 8500-9000 r/min, carrying out outward expansion of 10-20%, carrying out inward expansion of 2.5-4.5 in the range of 1-10 and carrying out overfeed ratio of-2.0-1.5%;

(4) weaving process

Weaving the twisted compound twisted yarn on an air jet loom at the speed of 550-750 revolutions per minute;

(5) impregnation step

The conditions of one bath dipping are as follows: the dipping solution mainly comprises closed isocyanate and epoxy resin, the solid content is 3.8%, the drying temperature is 155-165 ℃, and the tension is 1000-1500 daN; the drafting temperature is 235-245 ℃, and the tension is 2000-3500 DAN; the speed is 75-85 m/min.

The conditions of the two-bath impregnation treatment are as follows: the two-bath impregnation liquid takes RFL (resorcinol-formaldehyde-latex) as a main body, the solid content is 24.1%, the drying temperature is 155-165 ℃, and the tension is 1000-1500 daN; setting temperature is 235-245 ℃, and tension is 900-1100 daN; the speed is 75-85 m/min;

finally obtaining the fine denier high strength 930dtex/2 gum dipping cord fabric used for passenger radial tires.

Preferably, the preparation method of the impregnated cord fabric for the radial ply tire adopts the temperature of more than 210 ℃ and the air volume of more than 6800m in the solid phase polymerization process³The process conditions of/h are sufficient to activate the low molecular terminal hydroxyl groups and carboxyl groups of the polyester.

Preferably, in the spinning process, the preparation method of the gum dipping cord fabric for the passenger radial tire adopts the steps of ultralow melt extrusion by a screw extruder, melt distribution, a metering pump, a spinning assembly, cooling forming, oiling, stretching and shaping, loosening, meshing and winding to produce high-strength raw yarns which reach 930dtex standard; the protofilament index can reach that the strength is more than or equal to 7.8 cN/dtex; the breaking strength is more than or equal to 76N; the dry heat shrinkage rate is 3.2 +/-0.5%.

Preferably, in the spinning step and in the dipping step, the method for producing the dipped cord fabric for passenger radial tires sets the dipping process with the high-temperature draft zone temperature of 235 to 245 ℃ and the draft tension of more than 2000daN, and adjusts the draft/retraction ratio in a preferred range of 2.0 to 2.5%. A gum dipping process of tension hot drawing and a proper gum dipping formula system are designed, so that the strength retention rate of the cord is fully improved, and the gum dipping cord fabric meets the requirement of high strength.

The beneficial effects are that: 930dtex/2 gummed cord fabric for passenger radial tires prepared by the invention has high strength (more than or equal to 140N), definite elongation (3.5-4.0%) and small dry heat shrinkage rate (less than or equal to 2.0%), is used for replacing the conventional 1100dtex/2 products, and achieves the effects of reducing cost and lightening tires, therefore, companies decide to develop 930dtex/2 gummed cord fabric for passenger radial tires.

Drawings

FIG. 1 is a flow chart of the production process of the preparation method of the present invention.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

The implementation process comprises the following steps:

the preparation method of the gum dipping cord fabric for the passenger radial tire is realized by the following steps:

(1) solid-phase polymerization:

taking a polyester wet slice as a raw material, heating to fully activate low molecular terminal hydroxyl and carboxyl of polyester, so that chain growth reaction occurs between low molecular chains step by step, and the viscosity of the produced high-viscosity PET slice reaches more than 1.19 dl/g;

(2) a spinning process:

melting process: high viscosity PET chip in N₂Under protection, heating and melting the raw materials within the range of 280-300 ℃, and then feeding the raw materials into a spinning manifold, wherein the temperature of the spinning manifold is controlled at 280-300 ℃; producing high-strength protofilaments;

(3) twisting process

Twisting the produced high-strength precursor on a direct twisting machine at the ingot speed of 8500-9000 r/min, carrying out outward expansion of 10-20%, carrying out inward expansion of 2.5-4.5 in the range of 1-10 and carrying out overfeed ratio of-2.0-1.5%;

(4) weaving process

Weaving the twisted compound twisted yarn on an air jet loom at the speed of 550-750 revolutions per minute;

(5) impregnation step

The conditions of one bath dipping are as follows: the dipping solution mainly comprises closed isocyanate and epoxy resin, the solid content is 3.8%, the drying temperature is 155-165 ℃, and the tension is 1000-1500 daN; the drafting temperature is 235-245 ℃, and the tension is 2000-3500 DAN; the speed is 75-85 m/min.

The conditions of the two-bath impregnation treatment are as follows: the two-bath impregnation liquid takes RFL as a main body, the solid content is 24.1%, the drying temperature is 155-165 ℃, and the tension is 1000-1500 daN; setting temperature is 235-245 ℃, and tension is 900-1100 daN; the speed is 75-85 m/min;

finally obtaining the fine denier high strength 930dtex/2 gum dipping cord fabric used for passenger radial tires.

The applicant carried out a control run for each of the different steps therein.

Examples 1 to 3:

(1) solid phase polymerization

The improved solid-phase polymerization process adopts the temperature of more than 210 ℃ and the air quantity of more than 6800m³The process conditions of high temperature and large air volume promote the activation of the hydroxyl and carboxyl at the low molecular end of the polyester, so that the chain extension reaction between low molecular chains is carried out in the forward direction, and the molecular weight is further increased. Details are shown in the following table:

solid phase polymerization process and slicing index

By testing the adjustment of different temperatures and wind speeds, different effects can be obtained, and preparation is provided for the implementation of the subsequent steps. Preheating and solid-phase tackifying in a continuous solid-phase tackifying device until the intrinsic viscosity of the PET slices after treatment is 1.19-1.22 dl/g.

Examples 4 to 7

In step 2 of the preparation:

(2) melting process

Under the protection of N2, the high-viscosity sliced raw material is heated and melted at the temperature of 280-300 ℃ and then enters a spinning manifold, and the temperature of the spinning manifold is controlled at 280-300 ℃; then through the procedures of melt distribution pipe, metering pump, spinning assembly, slow cooling, sufficient cooling forming, oiling, multistage drawing, heat setting winding and the like, the high-strength polyester industrial yarn is produced. Details are shown in the following table:

melting temperature and strand index

Under the condition of different melting temperatures, the obtained polyester industrial yarns have different strengths; for the purpose of the present application, the temperature control range meeting the requirements is selected to prepare the indexes of the precursor.

Examples 8 to 11

The gum dipping in the preparation process is also an important link. The designed gum dipping process of tension hot drawing with the temperature of 235-245 ℃ and the drawing tension of more than 2000daN ensures that the gum dipped cord fabric meets the requirement of high strength characteristic by adjusting the drawing/retraction ratio of the tension of the drawing area and the setting area within a proper range. Details are shown in the following table:

dipping process and cord fabric index

The resulting strength properties of the shade fabrics are not the same through different operating conditions.

Examples 12 to 13

Compared with a common 1100dtex/2 polyester cord fabric sample, the fine denier high-strength 930dtex/2 cord fabric developed by the application has the specific comparison effect shown in the following table:

physical comparison of cord fabrics

The performance indexes of the two different fabrics are obviously different.

Example 14

As shown in the preparation flow shown in the attached figure 1, the high-viscosity PET chip raw material in the embodiment 13 is selected, and then the polyester industrial yarn has high performance through stretching, shaping and retracting of rollers and selecting the stretching and winding process conditions. Finally, by adjusting the stretching/retraction ratio of the tension of the stretching area and the setting area, designing a gum dipping process of tension hot stretching, and continuously optimizing the gum dipping process, the gum dipping cord fabric can reach the requirement of high strength, and the indexes of the gum dipping cord fabric of 930dtex/2 refer to the following table:

main characteristics of 930dtex/2 gum dipping cord fabric for passenger radial ply tire

The cord fabric has the performance which can be completely used for radial tires and has good performance.