阅读说明：本技术 一种防水链条的eva密封工艺 (EVA sealing process of waterproof chain ) 是由 吴小锐 于 2020-12-29 设计创作，主要内容包括：本发明涉及链条技术领域,具体涉及一种防水链条的EVA密封工艺,所述链齿包括齿根和齿头,所述齿头相互啮合,所述齿根之间的空槽填充有第一树脂体,所述齿根和第一树脂的上下表面均复合有第二树脂体,所述注塑密封工艺步骤：以EVA弹性体作为注塑树脂对拉链带进行注塑成型。本发明通过注塑工艺,在链齿的非啮合部位,即齿根之间的空槽填充树脂体,以达到防渗水的功效,同时为了提高树脂体的嵌入稳定性以及进一步提高防水性,树脂体通过注塑工艺一体填充到齿根的上下表面,形成完整连续的全面包覆齿根的EVA弹性体,因此齿根作为定位柱可以固定EVA弹性体的位置,使其不容易发生脱位或脱落,提高结构稳定性,也提高了防水性能。(The invention relates to the technical field of chains, in particular to an EVA (ethylene-vinyl acetate copolymer) sealing process for a waterproof chain, wherein each chain tooth comprises a tooth root and a tooth head, the tooth heads are meshed with each other, a first resin body is filled in a hollow groove between the tooth roots, second resin bodies are compounded on the upper surface and the lower surface of each of the tooth roots and the first resin, and the injection molding sealing process comprises the following steps: and carrying out injection molding on the zipper belt by taking the EVA elastomer as injection molding resin. The invention fills the resin body in the non-meshing part of the sprocket, namely the empty groove between the tooth roots through the injection molding process so as to achieve the effect of preventing water seepage, and simultaneously, in order to improve the embedding stability of the resin body and further improve the waterproofness, the resin body is integrally filled on the upper surface and the lower surface of the tooth roots through the injection molding process so as to form a complete and continuous EVA elastomer which completely covers the tooth roots, so that the tooth roots can be used as positioning columns to fix the position of the EVA elastomer, so that the EVA elastomer is not easy to dislocate or fall off, the structural stability is improved, and the waterproofness is also.)

1. The EVA sealing process of the waterproof chain is characterized in that: waterproof zipper includes two zipper tapes, the side of zipper tape all is provided with the side by side sprocket of a plurality of, the sprocket includes the tooth root and sets up in the tooth head in the tooth root outside, two zipper tapes tooth head intermeshing, empty groove between the tooth root is filled with first resin body, the upper surface of upper surface, the lower surface of tooth root, the upper surface of first resin body and the lower surface of first resin body of tooth root all compound has the second resin body, first resin body and second resin body are through injection molding sealing process integrated into one piece, first resin body and second resin body are the EVA elastomer, injection molding sealing process includes following step: the zipper tape with the toothed chain is placed in an injection mold, and injection molding and vulcanization are carried out by taking an EVA (ethylene vinyl acetate) elastomer as injection molding resin, wherein the EVA elastomer comprises the following raw materials in parts by weight:

the reinforcement is prepared by the following method:

(1) preparing polylactic acid particles into polylactic acid sheets;

(2) placing the polylactic acid sheet on a receiving platform in an electrostatic spinning device, and preparing a layer of polyacrylonitrile fiber film on the surface of the polylactic acid sheet by utilizing electrostatic spinning;

(3) and (3) crushing the polylactic acid sheets subjected to electrostatic spinning to 80-120 meshes to obtain the reinforcement.

2. The EVA sealing process of the waterproof chain according to claim 1, wherein: the thickness of the polylactic acid sheet is 1-3mm, and the thickness of the polyacrylonitrile fiber film is 100-300 mu m.

3. The EVA sealing process of the waterproof chain according to claim 1, wherein: the molar mass of the polylactic acid particles is 160000-180000 g/mol.

4. The EVA sealing process of the waterproof chain according to claim 1, wherein: the spinning solution adopted by the electrostatic spinning is 10-15 wt% of polyacrylonitrile solution, and the solvent of the polyacrylonitrile solution is dimethylacetamide.

5. The EVA sealing process of the waterproof chain according to claim 1, wherein: the spinning voltage of the electrostatic spinning is 15-25kV, the spinning flow rate is 0.4-0.5mL/h, and the fiber collecting distance is 10-15 cm.

6. The EVA sealing process of the waterproof chain according to claim 1, wherein: the flame retardant is at least one of red phosphorus, zinc borate and nano magnesium hydroxide.

7. The EVA sealing process of the waterproof chain according to claim 1, wherein: the lubricant is at least one of polyethylene wax, zinc oxide and magnesium oxide.

8. The EVA sealing process of the waterproof chain according to claim 1, wherein: the antioxidant is at least one of antioxidant 300, antioxidant 1010 and antioxidant DLTP.

9. The EVA sealing process of the waterproof chain according to claim 1, wherein: the ultraviolet absorbent is at least one of benzotriazole ultraviolet absorbent, benzophenone ultraviolet absorbent and hindered amine ultraviolet absorbent.

10. The EVA sealing process of the waterproof chain according to claim 1, wherein: the preparation method of the EVA comprises the following steps: mixing the raw materials, adding the mixture into a double-screw extruder for extrusion granulation, wherein the extrusion granulation temperature is 150-170 ℃.

Technical Field

The invention relates to the technical field of chains, in particular to an EVA (ethylene vinyl acetate) sealing process of a waterproof chain.

Background

Zippers (zippers), which are connectors for uniting or separating articles by means of a continuous arrangement of zipper teeth, are now widely used in clothing, bags, tents, etc. Due to the nature of the inter-engaging elements, even when the slide fastener is in a closed state, a large gap is formed between the elements, and thus the waterproof function cannot be achieved. The existing waterproof structure for the zipper is only to simply make a cloth belt on the back of the zipper teeth, although the waterproof structure can prevent water seepage to a certain extent, the permeated water is only absorbed by the cloth belt essentially and does not achieve the anti-seepage effect, and the cloth belt on the back is also easily clamped on the zipper teeth, so that the use experience is not high.

Disclosure of Invention

The invention aims to provide an EVA sealing process of a waterproof chain, aiming at the defects in the prior art.

The purpose of the invention is realized by the following technical scheme:

the utility model provides a waterproof chain's EVA sealing process, waterproof zipper include two zipper strips, the side of zipper strip all is provided with the side by side sprocket of a plurality of, the sprocket includes the tooth root and sets up in the tooth head in the tooth root outside, two zipper strips tooth head intermeshing, empty slot between the tooth root is filled has first resin body, the upper surface of tooth root, the lower surface of tooth root, the upper surface of first resin body and the lower surface of first resin body all have compounded the second resin body, first resin body and second resin body are through injection molding sealing technology integrated into one piece, first resin body and second resin body are the EVA elastomer, injection molding sealing process includes following step: the zipper tape with the toothed chain is placed in an injection mold, and injection molding and vulcanization are carried out by taking an EVA (ethylene vinyl acetate) elastomer as injection molding resin, wherein the EVA elastomer comprises the following raw materials in parts by weight:

the reinforcement is prepared by the following method:

(1) preparing polylactic acid particles into polylactic acid sheets;

(2) placing the polylactic acid sheet on a receiving platform in an electrostatic spinning device, and preparing a layer of polyacrylonitrile fiber film on the surface of the polylactic acid sheet by utilizing electrostatic spinning;

(3) and (3) crushing the polylactic acid sheets subjected to electrostatic spinning to 80-120 meshes to obtain the reinforcement.

The invention fills the resin body in the non-meshing part of the sprocket, namely the empty groove between the tooth roots through the injection molding process so as to achieve the effect of preventing water seepage, and simultaneously, in order to improve the embedding stability of the resin body and further improve the waterproofness, the resin body is integrally filled on the upper surface and the lower surface of the tooth roots through the injection molding process so as to form complete and continuous EVA completely coating the tooth roots, so that the tooth roots can be used as positioning columns to fix the position of the EVA, the EVA is not easy to dislocate or fall off, the structural stability is improved, and the waterproofness is also improved.

Furthermore, EVA as a casting material is required to have the following characteristics: 1. sufficient melt fluidity to enable the hollow groove to be fully filled; 2. sufficient mechanical strength makes it keep the integrality of structure in the repeated bending process, is difficult to appear becoming flexible, and first resin body is owing to receive the extrusion effect of tooth root often, consequently more needs better elasticity, makes it keep fully kick-backing the state of filling the dead slot, and second resin body is because the arm of force is longer, consequently more needs bending strength and elongation at break, avoids breaking or the plastic stretching that appears. Therefore, the invention provides the EVA composition, the EVA has soft texture, higher toughness and stronger melt fluidity, the vulcanization strengthening effect can be improved by adding a small amount of nano silicon dioxide, and the EVA still has enough melt fluidity. The invention also adds a polylactic acid-polyacrylonitrile fiber composite reinforcement body to enhance the mechanical property. The reinforcement is the layered composite structure particles of polylactic acid-polyacrylonitrile fibers, the polylactic acid has higher rigidity at normal temperature, the rigidity, namely the bending strength, of the second resin body can be better enhanced, and simultaneously, based on a rigid body toughening mechanism, the incompatible two phases are easy to generate defects such as silver characters and the like in the yield process, the bending energy is consumed, and the elongation at break is improved; the melting point of the polyacrylonitrile fiber is higher than 300 ℃, the polyacrylonitrile fiber is not melted in the melt extrusion or injection molding process, so the polyacrylonitrile fiber with poor fluidity is difficult to permeate into the empty groove. According to the invention, through designing the reinforcement body, the first resin body and the second resin body generate the difference of mechanical properties, and the requirements of different parts are met.

Wherein the thickness of the polylactic acid sheet is 1-3mm, and the thickness of the polyacrylonitrile fiber film is 100-300 μm. Limiting the thickness of both is equivalent to limiting the amount of both to function better.

Wherein the molar mass of the polylactic acid particles is 160000-180000 g/mol. The polylactic acid particles with the molar mass have better rigidity, and the effect of enhancing EVA is more obvious.

The spinning solution adopted by the electrostatic spinning is 10-15 wt% of polyacrylonitrile solution, and the solvent of the polyacrylonitrile solution is dimethylacetamide.

Wherein the spinning voltage of the electrostatic spinning is 15-25kV, the spinning flow rate is 0.4-0.5mL/h, and the fiber collecting distance is 10-15 cm.

Wherein, the vulcanizing agent is DCP or BPO.

Wherein the flame retardant is at least one of red phosphorus, zinc borate and nano magnesium hydroxide.

Wherein the lubricant is at least one of polyethylene wax, zinc oxide and magnesium oxide.

Wherein the antioxidant is at least one of antioxidant 300, antioxidant 1010 and antioxidant DLTP.

Wherein the ultraviolet absorbent is at least one of benzotriazole ultraviolet absorbent, benzophenone ultraviolet absorbent and hindered amine ultraviolet absorbent.

The preparation method of the EVA comprises the following steps: mixing the raw materials, adding the mixture into a double-screw extruder for extrusion granulation, wherein the extrusion granulation temperature is 150-170 ℃.

Wherein the injection molding temperature is 150-170 ℃, and the vulcanization temperature is 180-200 ℃.

The invention has the beneficial effects that: the invention fills the resin body in the non-meshing part of the sprocket, namely the empty groove between the tooth roots through the injection molding process so as to achieve the effect of preventing water seepage, and simultaneously, in order to improve the embedding stability of the resin body and further improve the waterproofness, the resin body is integrally filled on the upper surface and the lower surface of the tooth roots through the injection molding process so as to form complete and continuous EVA completely coating the tooth roots, so that the tooth roots can be used as positioning columns to fix the position of the EVA, the EVA is not easy to dislocate or fall off, the structural stability is improved, and the waterproofness is also improved.

Furthermore, EVA as a casting material is required to have the following characteristics: 1. sufficient melt fluidity to enable the hollow groove to be fully filled; 2. sufficient mechanical strength makes it keep the integrality of structure in the repeated bending process, is difficult to appear becoming flexible, and first resin body is owing to receive the extrusion effect of tooth root often, consequently more needs better elasticity, makes it keep fully kick-backing the state of filling the dead slot, and second resin body is because the arm of force is longer, consequently more needs tensile strength and elongation at break, avoids breaking or the plasticity is tensile appearing. Therefore, the invention provides the EVA composition, the EVA has soft texture, higher toughness and stronger melt fluidity, the vulcanization strengthening effect can be improved by adding a small amount of nano silicon dioxide, and the EVA still has enough melt fluidity. The invention also adds a polylactic acid-polyacrylonitrile fiber composite reinforcement body to enhance the mechanical property. The reinforcement is the layered composite structure particles of polylactic acid-polyacrylonitrile fibers, the polylactic acid has higher rigidity at normal temperature, the rigidity, namely tensile strength, of the second resin body can be better enhanced, and simultaneously, based on a rigid body toughening mechanism, the incompatible two phases are easy to generate defects such as silver characters and the like in the yield process, the bending energy is consumed, and the elongation at break is improved; the melting point of the polyacrylonitrile fiber is higher than 300 ℃, the polyacrylonitrile fiber is not melted in the melt extrusion or injection molding process, so the polyacrylonitrile fiber with poor fluidity is difficult to permeate into the empty groove. According to the invention, through designing the reinforcement body, the first resin body and the second resin body generate the difference of mechanical properties, and the requirements of different parts are met.

Drawings

FIG. 1 is a top view of the structure of the waterproof slide fastener of the present invention;

FIG. 2 is a structural sectional view of the waterproof slide fastener of the present invention;

the reference signs are: 1-zipper tape, 2-tooth head, 3-tooth root, 4-first resin body and 5-second resin body.

Detailed Description

The invention is further described with reference to the following examples.

Example 1

The utility model provides a waterproof chain's EVA sealing process, waterproof zipper include two zipper strips 1, the side of zipper strip 1 all is provided with the sprocket that a plurality of is side by side, the sprocket includes tooth root 3 and sets up in the tooth head 2 in the 3 outsides of tooth root, two zipper strips 1 tooth head 2 intermeshing, the dead slot between the tooth root 3 is filled with first resin body 4, the upper surface of tooth root 3, the lower surface of tooth root 3, the upper surface of first resin body 4 and the lower surface of first resin body 4 all have compounded second resin body 5, first resin body 4 and second resin body 5 are through injection molding sealing process integrated into one piece, first resin body 4 and second resin body 5 are the EVA elastomer, injection molding sealing process includes following step: the zipper tape 1 with the toothed chain is placed in an injection mold, and injection molding and vulcanization are carried out by taking an EVA (ethylene vinyl acetate) elastomer as injection molding resin, wherein the EVA elastomer comprises the following raw materials in parts by weight:

the reinforcement is prepared by the following method:

(1) preparing polylactic acid particles into polylactic acid sheets;

(2) placing the polylactic acid sheet on a receiving platform in an electrostatic spinning device, and preparing a layer of polyacrylonitrile fiber film on the surface of the polylactic acid sheet by utilizing electrostatic spinning;

(3) and (3) crushing the polylactic acid sheets subjected to electrostatic spinning to 80-120 meshes to obtain the reinforcement.

The thickness of the polylactic acid sheet is 1mm, and the thickness of the polyacrylonitrile fiber film is 100 micrometers.

Wherein the polylactic acid particles have a molar mass of 160000 g/mol.

The spinning solution adopted by the electrostatic spinning is 10 wt% of polyacrylonitrile solution, and the solvent of the polyacrylonitrile solution is dimethylacetamide.

The spinning voltage of the electrostatic spinning is 15kV, the spinning flow rate is 0.4mL/h, and the fiber collecting distance is 10 cm.

Wherein the vulcanizing agent is DCP.

The flame retardant is a composition consisting of red phosphorus and zinc borate according to the weight ratio of 1: 1.

Wherein the lubricant is polyethylene wax.

Wherein the antioxidant is antioxidant 300.

Wherein the ultraviolet absorbent is a benzotriazole ultraviolet absorbent.

The preparation method of the EVA comprises the following steps: mixing the raw materials, adding the mixture into a double-screw extruder for extrusion granulation, wherein the temperature of the extrusion granulation is 150 ℃.

Wherein the injection molding temperature is 150 ℃, and the vulcanization temperature is 180 ℃.

Example 2

The utility model provides a waterproof chain's EVA sealing process, waterproof zipper include two zipper strips 1, the side of zipper strip 1 all is provided with the sprocket that a plurality of is side by side, the sprocket includes tooth root 3 and sets up in the tooth head 2 in the 3 outsides of tooth root, two zipper strips 1 tooth head 2 intermeshing, the dead slot between the tooth root 3 is filled with first resin body 4, the upper surface of tooth root 3, the lower surface of tooth root 3, the upper surface of first resin body 4 and the lower surface of first resin body 4 all have compounded second resin body 5, first resin body 4 and second resin body 5 are through injection molding sealing process integrated into one piece, first resin body 4 and second resin body 5 are the EVA elastomer, injection molding sealing process includes following step: the zipper tape 1 with the toothed chain is placed in an injection mold, and injection molding and vulcanization are carried out by taking an EVA (ethylene vinyl acetate) elastomer as injection molding resin, wherein the EVA elastomer comprises the following raw materials in parts by weight:

the reinforcement is prepared by the following method:

(1) preparing polylactic acid particles into polylactic acid sheets;

(2) placing the polylactic acid sheet on a receiving platform in an electrostatic spinning device, and preparing a layer of polyacrylonitrile fiber film on the surface of the polylactic acid sheet by utilizing electrostatic spinning;

(3) and (3) crushing the polylactic acid sheets subjected to electrostatic spinning to 80-120 meshes to obtain the reinforcement.

The thickness of the polylactic acid sheet is 3mm, and the thickness of the polyacrylonitrile fiber film is 300 mu m.

Wherein the polylactic acid particles have a molar mass of 180000 g/mol.

The spinning solution adopted by the electrostatic spinning is 15 wt% of polyacrylonitrile solution, and the solvent of the polyacrylonitrile solution is dimethylacetamide.

The electrostatic spinning voltage is 25kV, the spinning flow rate is 0.5mL/h, and the fiber collecting distance is 15 cm.

Wherein the vulcanizing agent is BPO.

The flame retardant is a composition consisting of zinc borate and nano magnesium hydroxide in a weight ratio of 1: 1.

Wherein the lubricant is magnesium oxide.

Wherein the antioxidant is antioxidant 1010.

Wherein the ultraviolet absorbent is benzophenone ultraviolet absorbent.

The preparation method of the EVA comprises the following steps: mixing the raw materials, adding the mixture into a double-screw extruder for extrusion granulation, wherein the temperature of the extrusion granulation is 170 ℃.

Wherein the injection molding temperature is 170 ℃, and the vulcanization temperature is 200 ℃.

Example 3

The utility model provides a waterproof chain's EVA sealing process, waterproof zipper include two zipper strips 1, the side of zipper strip 1 all is provided with the sprocket that a plurality of is side by side, the sprocket includes tooth root 3 and sets up in the tooth head 2 in the 3 outsides of tooth root, two zipper strips 1 tooth head 2 intermeshing, the dead slot between the tooth root 3 is filled with first resin body 4, the upper surface of tooth root 3, the lower surface of tooth root 3, the upper surface of first resin body 4 and the lower surface of first resin body 4 all have compounded second resin body 5, first resin body 4 and second resin body 5 are through injection molding sealing process integrated into one piece, first resin body 4 and second resin body 5 are the EVA elastomer, injection molding sealing process includes following step: the zipper tape 1 with the toothed chain is placed in an injection mold, and injection molding and vulcanization are carried out by taking an EVA (ethylene vinyl acetate) elastomer as injection molding resin, wherein the EVA elastomer comprises the following raw materials in parts by weight:

the reinforcement is prepared by the following method:

(1) preparing polylactic acid particles into polylactic acid sheets;

(2) placing the polylactic acid sheet on a receiving platform in an electrostatic spinning device, and preparing a layer of polyacrylonitrile fiber film on the surface of the polylactic acid sheet by utilizing electrostatic spinning;

(3) and (3) crushing the polylactic acid sheets subjected to electrostatic spinning to 80-120 meshes to obtain the reinforcement.

The thickness of the polylactic acid sheet is 2mm, and the thickness of the polyacrylonitrile fiber film is 200 mu m.

Wherein the polylactic acid particles have a molar mass of 170000 g/mol.

The spinning solution adopted by the electrostatic spinning is 12.5 wt% of polyacrylonitrile solution, and the solvent of the polyacrylonitrile solution is dimethylacetamide.

Wherein the spinning voltage of the electrostatic spinning is 20kV, the spinning flow rate is 0.45mL/h, and the fiber collecting distance is 12.5 cm.

Wherein the vulcanizing agent is DCP.

Wherein the flame retardant is a composition consisting of red phosphorus and nano magnesium hydroxide according to the weight ratio of 1: 1.

Wherein the lubricant is zinc oxide.

Wherein the antioxidant is DLTP antioxidant.

Wherein the ultraviolet absorbent is hindered amine ultraviolet absorbent.

The preparation method of the EVA comprises the following steps: mixing the raw materials, adding the mixture into a double-screw extruder for extrusion granulation, wherein the temperature of the extrusion granulation is 160 ℃.

Wherein the injection molding temperature is 160 ℃, and the vulcanization temperature is 190 ℃.

Comparative example 1

This comparative example differs from example 3 in that:

the reinforcement is obtained by crushing polylactic acid slices which are not subjected to spinning treatment.

Comparative example 2

This comparative example differs from example 2 in that:

the reinforcement body is composed of polylactic acid particles and polyacrylonitrile fibers according to the proportion of 10: 1.

The EVA of example 3, comparative example 1 and comparative example 2 were injection molded into ASTM standard specimens for mechanical property testing, and the results are shown in the following table:

	tensile Strength (MPa)	Elongation at Break (%)
			Example 3	25.1	508
Comparative example 1	29.2	425
			Comparative example 2	27.5	622

As can be seen from the above data, for the improvement of mechanical properties, the reinforcement of the invention is superior to that of comparative example 1 in elongation at break, and the other properties are not as good as those of the comparative example of the polylactic acid particles or the mixture of the polylactic acid particles and the polyacrylonitrile fibers which are directly added, because the properties of the blend have a great correlation with the dispersion state of the dispersed phase, the reinforcement of the invention is formed by compounding the polylactic acid layer and the polyacrylonitrile layer, the polylactic acid layer and the polyacrylonitrile layer are always polymerized together and are not dispersed, so the reinforcement effect on EVA is rather ineffective, only the fiber structure of polyacrylonitrile is relied on to highlight the advantage of elongation at break, but still inferior to that of the mixture of the polylactic acid particles and the polyacrylonitrile fibers which are directly added.

The present invention also observed the results of bending the same site at an angle of-150 ° - +150 ° for the waterproof zippers of example 3, comparative example 1 and comparative example 2, and repeating the bending 2000 times. The resin body of the waterproof slide fastener of the embodiment 3 has no obvious sign of loosening or falling off, the phenomenon of whitening and even cracking is caused in the comparative example 1 because the polylactic acid in the EVA has overlarge brittleness and is easy to break without the support of polyacrylonitrile fiber, and the phenomenon of generating gaps and even loosening is caused in the comparative example 2 because the polylactic acid can permeate into the empty slot along with the EVA, and therefore, the brittleness of the first resin body 4 is larger, and the plastic deformation is easy to generate in the repeated bending and compression processes. Therefore, the EVA of the invention is not focused on improving the mechanical property, but on forming two resin bodies with different mechanical properties to meet the performance requirements of different parts of the waterproof zipper.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.