CN108943515B - Integral forming method of thermoplastic polyurethane component by using plate vulcanizing equipment - Google Patents
Integral forming method of thermoplastic polyurethane component by using plate vulcanizing equipment Download PDFInfo
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- CN108943515B CN108943515B CN201810617020.1A CN201810617020A CN108943515B CN 108943515 B CN108943515 B CN 108943515B CN 201810617020 A CN201810617020 A CN 201810617020A CN 108943515 B CN108943515 B CN 108943515B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/76—Cores
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2075/00—Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
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- Health & Medical Sciences (AREA)
- Oral & Maxillofacial Surgery (AREA)
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- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
The integral forming process of thermoplastic polyurethane member with plate vulcanizing apparatus includes the steps of preheating the mold, filling film, closing mold, secondary heating, maintaining pressure, cooling, demolding and other steps to set the thermoplastic polyurethane in relatively closed mold cavity, maintaining the mold at 100 deg.c to evaporate water vapor before setting the product, maintaining the mold in dry environment and avoiding photolysis or hydrolysis of polyurethane material. The final product can keep the physicochemical properties basically consistent with those of the original film without material property loss caused by secondary processing. The thermoplastic polyurethane member obtained by the method is of an integral structure, has no adhesive seams or adhesive strips, is uniform in integral thickness, reduces the weight of the member, and obviously improves the structural strength, the air tightness and the bearing capacity of the member and the service life of the member by integral forming because the strength of the seams of the polyurethane material is greatly lower than that of the material when the polyurethane material is spliced and used.
Description
Technical Field
The invention relates to the technical field of manufacturing of individual protective clothing and airtight structures, in particular to an integral forming preparation method of a thermoplastic polyurethane thin-wall component.
Background
The individual protective clothing is a kind of clothing which provides respiratory protection, thermal protection and air pressure protection for people when the people are separated from the normal living environment and can enable the people to have certain activity. Such garments typically require a completely or partially intact air-tight structure for maintaining air pressure on the body surface and providing an appropriate partial pressure of oxygen in the nasal region of the human mouth for the person to breathe properly. Due to the irregular structure of the human body, the airtight structure is usually formed by bonding rubber or plastic materials after being made into a film, for example, diving suits are formed by bonding after being cut by butyl tapes, spacesuits are formed by bonding after being cut by natural films, mountaineering suits are formed by high-frequency welding after being cut by films such as polytetrafluoroethylene, polyvinyl chloride or polyurethane.
The manufacture of products with such structures usually involves making a planar film from a material with air tightness, printing, cutting, and splicing by gluing or heating according to the structure of the garment. This molding process results in a loss of structural seal, and also results in a reduction in structural strength and an increase in structural weight.
Disclosure of Invention
The invention aims to provide a method for integrally forming a thermoplastic polyurethane member by using a flat-plate vulcanizing device so as to improve the performances of the thermoplastic polyurethane member product, such as air tightness, pressure-bearing capacity, structural reliability, service life and the like.
The invention is realized by the following technical scheme:
a method for integrally forming a thermoplastic polyurethane member by using a press vulcanization device, comprising the steps of:
step 1: selecting a thermoplastic polyurethane film;
step 2: preparing a mold, wherein the mold comprises a mold core, an upper mold cavity and a lower mold cavity;
and step 3: and manufacturing the thermoplastic polyurethane component by using a vulcanizing press.
Further, a thermoplastic polyurethane film with uniform thickness is selected in the step 1, and the thickness of the film is selected according to 1.2-1.5 times of the maximum thickness of the component.
Furthermore, in the step 2, 3Cr2Mo plastic die steel is selected to manufacture a die core, an upper die cavity and a lower die cavity; the outer surface of the mold core is designed according to the structure and the size of the inner wall of the component; the inner concave surfaces of the upper die cavity and the lower die cavity are designed according to the structure and the size of the outer wall of the component.
Further, the step 3 further comprises the following steps:
step 3.1: mold preheating
Placing the mold core into the lower mold cavity, and closing the upper mold cavity to form an integral mold; putting the mould into a plate vulcanizing machine, and preheating the mould;
step 3.2: preparation for filling film
Taking the heated mould out of the vulcanizing press, and carrying out air cooling or natural cooling on the mould;
step 3.3: filling film
Taking down the upper die cavity, lifting the die core, and spreading the thermoplastic polyurethane film in the lower die cavity; then putting down the mold core and pressing the mold core on the film material of the lower mold cavity; then spreading a thermoplastic polyurethane film above the mold core; then the upper die cavity is buckled on a die core with the membrane material to form an integral die which is filled with the membrane material in the die;
step 3.4: die assembly
Putting the mould into a flat vulcanizing machine, carrying out secondary heating on the mould through the flat vulcanizing machine, and pressurizing the mould;
step 3.5: pressure maintaining cooling
When the mould reaches the rheological temperature point of the thermoplastic polyurethane, closing the heating of the vulcanizing press, keeping the pressure unchanged, and carrying out air cooling on the vulcanizing press;
step 3.6: demoulding
When the temperature of the mold is reduced to room temperature, taking the mold out of the flat vulcanizing machine; and taking down the upper die cavity, hoisting the die core, and taking down the integrally formed thermoplastic polyurethane component from the die core.
Further, the temperature for preheating the die in the step 3.1 is 150-170 ℃.
Further, in the step 3.2, the temperature of the mold is reduced to the film filling temperature of 120-140 ℃.
Further, in the step 3.4, the mold is heated for the second time to reach 140-160 ℃, and is pressurized to reach 10-15 MPa.
Further, a screw extrusion plasticizing device is selected for the thermoplastic polyurethane film material, and a polyurethane film with the thickness of 0.7mm is manufactured.
The technical scheme of the invention has the following beneficial technical effects:
1. in the preparation process of the component, the thermoplastic polyurethane is shaped in a relatively closed mold cavity, and the mold is kept at more than 100 ℃ before the product is shaped, so that water vapor is evaporated, the mold is kept in a dry environment, and the polyurethane material is prevented from generating photolysis or hydrolysis. The film filling temperature of the polyurethane material is below 160 ℃, the residence time from film filling to temperature reduction to the rheological temperature point of the polyurethane material is less than 20 minutes, the thermal decomposition of the material cannot be caused, the product can keep the physicochemical property basically consistent with that of the original film material, and the material property loss caused by secondary processing cannot be generated.
2. The special-shaped member is of an integral structure, has no bonding seam or bonding strip, has uniform integral thickness, reduces the weight of the member, and obviously improves the structural strength, the air tightness, the bearing capacity and the service life of the member by integral molding because the strength of the seam of the polyurethane material is greatly lower than that of the material when the polyurethane material is spliced and used.
Drawings
FIG. 1 is a flow chart of a method of integrally forming a thin-walled thermoplastic polyurethane member using a press vulcanization apparatus according to the present invention;
FIG. 2 is a schematic structural view of an integrally molded article of a thin-walled member according to an embodiment of the present invention;
FIG. 3 is a schematic view of a mold structure according to an embodiment of the present invention;
FIG. 4 is a schematic view of an integral thin-walled member forming process according to an embodiment of the present invention;
FIG. 5 is a schematic illustration of a thin-walled component article demolding process according to an embodiment of the invention.
Reference numbers in the figures:
1-upper die cavity, 2-die core, 3-lower die cavity, 4-die positioning support, 5-plate vulcanizing machine, 6-demoulding tool and 7-integrally forming thin-wall component.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
The thermoplastic polyurethane is a polyurethane material with physical crosslinking characteristics, has the environmental protection characteristics of no need of vulcanization crosslinking, repeatable thermal processing, recyclability and the like, is a high-modulus and high-elasticity polyurethane variety which is not provided with or replaceable by other types of polyurethanes such as cast polyurethane, mixed polyurethane and the like, and is mainly applied to products with thin film sheet structures. The raw material form is spherical or ellipsoidal granular material with the diameter of 2mm to 5mm, the granular material is melted, homogenized and extruded through screw extrusion plasticizing equipment, and finally the granular material is rolled into a film material.
With the development of 3D manufacturing technology, the conventional method of forming a three-dimensional structure by processing a planar material for multiple times is being replaced by three-dimensional manufacturing technology such as 3D printing. However, no mature method has been found for the overall production of thermoplastic polyurethanes due to the special characteristics of polyurethane materials such as high elasticity and thermal decomposition. Especially for the large-size special-shaped thin-wall component, due to the high viscosity of polyurethane, the uniformity and the integrity of the component cannot be ensured due to the overlarge extrusion pressure requirement when the polyurethane is processed by adopting a melting method; when the polyurethane is processed by a solution method, the polyurethane stays in a material melting temperature range for a long time, so that raw materials are pyrolyzed and hydrolyzed, the performance of a product is obviously reduced, and the surface uniformity of the product is poor due to the high-viscosity characteristic of the polyurethane.
The thermoplastic polyurethane material can show the high elasticity of rubber materials, can also show the high strength of plastic materials, has excellent wear resistance, oil resistance and the like, and is a material with various purposes and wide application. By a better forming method, the process method of secondary processing and forming by using the film material is changed, and the application of the thermoplastic polyurethane material in the special-shaped thin-wall component can be expanded.
The invention provides a method for integrally forming a thermoplastic polyurethane component by using plate vulcanization equipment, which adopts a thermoplastic polyurethane material to manufacture individual protective clothing and comprises the following steps:
the method comprises the following steps: selection of thermoplastic polyurethane film
And selecting a thermoplastic polyurethane film material with uniform thickness, wherein the thickness of the film material is selected according to 1.2-1.5 times of the maximum thickness of the component.
Step two: preparation of thin-wall component mold
According to the integral structure of the component, 3Cr2Mo plastic die steel is selected to manufacture a die core, an upper die cavity and a lower die cavity. The outer surface of the mould core is designed according to the structure and the size of the inner wall of the component. The inner concave surfaces of the upper die cavity and the lower die cavity are designed according to the structure and the size of the outer wall of the component.
Step three: method for manufacturing special-shaped component by using flat vulcanizing machine
3.1 preheating of the mold
And placing the mold core into the lower mold cavity, and closing the upper mold cavity to form the integral mold. Putting the die into a flat vulcanizing machine, and preheating the die to 150-170 ℃.
3.2 film filling preparation
And taking the heated mould out of the flat vulcanizing machine, and carrying out air cooling or natural cooling on the mould to reach the film filling temperature of 120-140 ℃.
3.3 filling the film
And taking down the upper die cavity, lifting the die core, and flatly paving the thermoplastic polyurethane film in the lower die cavity. Then the mould core is put down and pressed on the membrane material of the lower mould cavity. And then spreading a thermoplastic polyurethane film above the mold core. And then the upper die cavity is buckled on a die core with the membrane material to form an integral die which is filled with the membrane material in the die.
3.4 closing the dies
And (3) putting the die into a flat vulcanizing machine, carrying out secondary heating on the die to 140-160 ℃ through the flat vulcanizing machine, and pressurizing the die by 10-15 MPa.
3.5 pressure maintaining Cooling
And when the mould reaches the rheological temperature point of the thermoplastic polyurethane, closing the heating of the vulcanizing press, keeping the pressurization unchanged, and carrying out air cooling on the vulcanizing press.
3.6 demolding
When the temperature of the mold is reduced to room temperature, the mold is taken out of the press vulcanizer. And taking down the upper die cavity, hoisting the die core, and taking down the integrally formed component from the die core.
The preparation process of the present invention will be described in further detail with reference to examples.
Referring to fig. 1, a preferred embodiment of the present invention provides a method for integrally molding a thermoplastic polyurethane profile member using a press vulcanization apparatus, comprising the steps of:
the method comprises the following steps: selection of thermoplastic polyurethane film
A polyurethane raw material with the trademark DP9370AU is adopted, and screw extrusion plasticizing equipment is selected to manufacture a polyurethane film with the thickness of 0.7 mm.
Step two: preparation of thin-wall component mold
According to the product structure requirement of fig. 2, a mold is manufactured, 3Cr2Mo plastic mold steel is selected, a mold core 2, an upper mold cavity 1 and a lower mold cavity 3 are manufactured, and the upper mold cavity 1, the mold core 2 and the lower mold cavity 3 are positioned and fixed through a mold positioning support 4, as shown in fig. 3. The size of the outer surface of the mold core is 0.5mm smaller than the size of the inner surfaces of the upper mold cavity and the lower mold cavity, and the size is the thickness of the component product.
Step three: method for manufacturing special-shaped component by using flat vulcanizing machine
3.1 preheating of the mold
And placing the mold core 2 into the lower mold cavity 3, and closing the upper mold cavity 1 to form the integral mold. Putting the mould into a 350t flat vulcanizing machine 5, and preheating the mould to 150-170 ℃.
3.2 film filling preparation
And taking the heated mould out of the flat vulcanizing machine 5, and carrying out air cooling or natural cooling on the mould by using an electric fan to reach the film filling temperature of 120-140 ℃.
3.3 filling the film
And taking down the upper die cavity 1, lifting the die core 2, and flatly paving the thermoplastic polyurethane film in the lower die cavity 3. The mould core 2 is then lowered and pressed against the film material in the lower mould cavity 3. And then the thermoplastic polyurethane film is flatly laid on the die core 2. And then the upper die cavity 1 is buckled on a die core 2 with the film material to form an integral die which is filled with the film material in the die.
3.4 closing the dies
And (3) putting the die into a vulcanizing press 5, carrying out secondary heating on the die to 140-160 ℃ through the vulcanizing press 5, and pressurizing the die by 15MPa at the same time, as shown in figure 4.
3.5 pressure maintaining Cooling
When the mold reaches the rheological temperature point of the thermoplastic polyurethane, the heating of the press vulcanizer 5 is turned off, but the pressurization is kept unchanged, and the press vulcanizer 5 is air-cooled by an electric fan.
3.6 demolding
When the mold temperature is lowered to room temperature, the mold is taken out of the press vulcanizer 5. The upper mould cavity 1 is removed, the mould core 2 is lifted, the mould positioning bracket 4 is fixed in the demoulding tool 6 by means of the demoulding tool 6, and then the integrally formed component is removed from the mould core 2, as shown in figure 5, and an integrally formed thin-walled component 7 with the thickness of 0.5mm can be obtained.
TABLE 1
As shown in the above Table 1, the performance parameters of the thermoplastic polyurethane granules, the molded product and the integrally molded member manufactured according to the example were measured, respectively, and the performance parameters include density, tensile strength and elongation at break, and the measurement results show that the density and mechanical properties of the integrally molded member are almost unchanged from those of the granules and the film-formed product in the original state, the original physical properties of the thermoplastic polyurethane material are retained to the maximum extent, and the airtightness and structural integrity of the member are obtained without further processing after the integral molding.
In conclusion, the invention provides an integral molding method of a thermoplastic polyurethane component by utilizing a plate vulcanizing device, in the preparation process of the component, the thermoplastic polyurethane is shaped in a relatively closed mold cavity through the steps of mold preheating, film filling, mold closing, secondary heating, pressure maintaining cooling, demolding and the like, the mold is kept at more than 100 ℃ before the product is shaped, water vapor is evaporated, the mold is kept in a dry environment, and the polyurethane material is prevented from being photolyzed or hydrolyzed. The final product can keep the physicochemical properties basically consistent with those of the original film without material property loss caused by secondary processing. The special-shaped member obtained by the method is of an integral structure, has no adhesive seams or adhesive strips, is uniform in integral thickness, reduces the weight of the member, and obviously improves the structural strength, the air tightness and the bearing capacity of the member and the service life of the member by integral forming because the strength of the seams of the polyurethane material is greatly lower than that of the material when the polyurethane material is spliced and used.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.
Claims (6)
1. A method for integrally forming a thermoplastic polyurethane member by using a plate vulcanizing device is characterized by comprising the following steps:
step 1: selecting a thermoplastic polyurethane film;
step 2: preparing a mold, wherein the mold comprises a mold core, an upper mold cavity and a lower mold cavity;
and step 3: manufacturing the thermoplastic polyurethane component by using a vulcanizing press;
the step 3 further comprises the following steps:
step 3.1: mold preheating
Placing the mold core into the lower mold cavity, and closing the upper mold cavity to form an integral mold; putting the mould into a plate vulcanizing machine, and preheating the mould;
step 3.2: preparation for filling film
Taking the heated mould out of the vulcanizing press, and carrying out air cooling or natural cooling on the mould; in the step 3.2, the temperature of the die is reduced to 120-140 ℃ of film filling temperature;
step 3.3: filling film
Taking down the upper die cavity, lifting the die core, and spreading the thermoplastic polyurethane film in the lower die cavity; then putting down the mold core and pressing the mold core on the film material of the lower mold cavity; then spreading a thermoplastic polyurethane film above the mold core; then the upper die cavity is buckled on a die core with the membrane material to form an integral die which is filled with the membrane material in the die;
step 3.4: die assembly
Putting the mould into a flat vulcanizing machine, carrying out secondary heating on the mould through the flat vulcanizing machine, and pressurizing the mould;
step 3.5: pressure maintaining cooling
When the mould reaches the rheological temperature point of the thermoplastic polyurethane, closing the heating of the vulcanizing press, keeping the pressure unchanged, and carrying out air cooling on the vulcanizing press;
step 3.6: demoulding
When the temperature of the mold is reduced to room temperature, taking the mold out of the flat vulcanizing machine; and taking down the upper die cavity, hoisting the die core, and taking down the integrally formed thermoplastic polyurethane component from the die core.
2. The method for integrally forming a thermoplastic polyurethane member by using a vulcanizing press according to claim 1, wherein the thermoplastic polyurethane film having a uniform thickness is selected in the step 1, and the thickness of the film is selected to be 1.2 to 1.5 times the maximum thickness of the member.
3. The method for integrally forming a thermoplastic polyurethane member by using a vulcanizing press according to claim 1, wherein 3Cr2Mo plastic die steel is selected in the step 2 to manufacture the mold core, the upper mold cavity and the lower mold cavity; the outer surface of the mold core is designed according to the structure and the size of the inner wall of the component; the inner concave surfaces of the upper die cavity and the lower die cavity are designed according to the structure and the size of the outer wall of the component.
4. The method for integrally molding a thermoplastic polyurethane member using a press vulcanization equipment according to claim 1, wherein the temperature for preheating the mold in the step 3.1 is 150 to 170 ℃.
5. The method for integrally molding a thermoplastic polyurethane member by using a vulcanizing press as claimed in claim 1, wherein the mold is heated for the second time in step 3.4 to a temperature of 140 to 160 ℃ and pressurized to a pressure of 10 to 15 MPa.
6. The method for integrally molding a thermoplastic polyurethane member using a vulcanizing press according to claim 1, wherein the thermoplastic polyurethane film is formed into a polyurethane film having a thickness of 0.7mm by a screw extrusion plasticizing apparatus.
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| CN201810617020.1A CN108943515B (en) | 2018-06-15 | 2018-06-15 | Integral forming method of thermoplastic polyurethane component by using plate vulcanizing equipment |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5611223A (en) * | 1979-07-09 | 1981-02-04 | Hitachi Chem Co Ltd | Manufacture of interior material for automobile and the like |
| CN206855838U (en) * | 2017-01-20 | 2018-01-09 | 无锡市万丰橡胶有限公司 | A kind of secondary preforming sulfurizing mould of rubber |
| CN107866935A (en) * | 2017-06-06 | 2018-04-03 | 湖北航天化学技术研究所 | A kind of thermoplastic polyurethane product forming process for being used for extraordinary airtight clothes |
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2018
- 2018-06-15 CN CN201810617020.1A patent/CN108943515B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5611223A (en) * | 1979-07-09 | 1981-02-04 | Hitachi Chem Co Ltd | Manufacture of interior material for automobile and the like |
| CN206855838U (en) * | 2017-01-20 | 2018-01-09 | 无锡市万丰橡胶有限公司 | A kind of secondary preforming sulfurizing mould of rubber |
| CN107866935A (en) * | 2017-06-06 | 2018-04-03 | 湖北航天化学技术研究所 | A kind of thermoplastic polyurethane product forming process for being used for extraordinary airtight clothes |
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| CN108943515A (en) | 2018-12-07 |
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