CN103568306A - Forming mold for TPU membrane and method of preparing the TPU membrane by utilization of the mold - Google Patents

Abstract

The invention provides a forming mold for a TPU membrane. The mold is provided with a plurality of recesses. An angle R1 formed between the inner wall and the bottom surface of each of the recesses is less than the minimum bending angle R when the TPU membrane is heated to be in a glassy state, and therefore air channels are formed due to the angle difference between the R1 and the R when the TPU membrane and the forming mold are connected. The bottom of each of the recesses is provided with a plurality of air venting channels in the horizontal direction, thus communicating the air channels through the air venting channels and forming an air channel network in the forming mold. Positions except the recesses, which have no influence on the appearance of a finished product of the TPU membrane, are provided with a plurality of air venting holes which are communicated with the air channel network and used for venting air.

Description

The mould of TPU film and utilize the method for preparing TPU film of this mould

Technical field

The present invention relates to a kind of TPU(TPU) mould of film, more specifically, be the exhaust setting about this mould, and utilize this mould to prepare the method for TPU film.

Background technology

The TPU diaphragm that is used in computer keyboard that adopts prior art to make; it as shown in figure 13; how to have in appearance a kind of marking forming in manufacturing forming process because of the steam vent on mould, in the field of business leading to is called " vacuum eye ", affects attractive in appearance and use feel.

Summary of the invention

The object of the invention is to, a kind of method of mould and manufacture TPU film of TPU film is provided, make to adopt this mould and method to manufacture the product that completes of moulding, there is no in appearance the marking forming because of die venting hole.

To achieve these goals, the present invention is by the following technical solutions:

A kind of mould of TPU film, it is characterized in that, on described mould, offer some recesses, the angle R1 forming between the inwall of described each recess and bottom surface is less than the minimum warpage angle R when TPU film is heated as glassy state, make when TPU film engages with mould, due to the differential seat angle of R and R1, at TPU film, form pore road; In the bottom of described each recess, be provided with in the horizontal direction many exhaust ducts, each pore road is communicated with by each exhaust duct, and in described mould, forms the network in pore road; Beyond described each recess and do not affect the position of TPU film finished product outward appearance, offer some and the steam vent for exhaust pore road network-in-dialing.

The mould of TPU film as above, wherein, described mould can be divided into a plurality of modules, forms described mould after combination.

The mould of TPU film as above, wherein, described mould can be divided into upper and lower two modules, and these two modules are in conjunction with the described mould of rear composition; On the correspondence position of the faying face of these two modules, offer respectively groove, two modules in conjunction with time corresponding groove combination form described exhaust duct.

The mould of TPU film as above, preferably, the width in described pore road is below 0.05mm.

A manufacture method for TPU film, step is as follows:

(1) TPU film is heated to it and becomes glassy state;

(2) the TPU film that is heated to glassy state is engaged with mould;

(3) mould exhaust moulding cooling make the sizing of TPU film;

(4) sizing after the demoulding of TPU film and cut rim charge, obtain TPU film finished product;

Wherein, described mould is the mould of the TPU film described in any one in claims 1 to 3.

The manufacture method of TPU film as above, preferably, the width in described pore road is below 0.05mm.

Beneficial effect of the present invention is:

The preparation method of the mould of TPU film provided by the invention and TPU film, while utilizing TPU to be heated as glassy state, its minimum warpage angle is R, and in the making of the mould of TPU film, the recess that the angle of offering inwall and bottom surface on mould is R1, make R be greater than R1, thereby form pore road in recess bottom, and utilize the pore exhaust that begins to rehearse in the position that does not affect finished product outward appearance of this pore road, thereby the TPU film finished product that order is made, does not have the marking forming because of steam vent in appearance.

Exhaust cloth at mould of the present invention is set up, and also the design of mould can be divided into a plurality of modules if desired, and vent is drawn to the molded surface in product, to realize steam vent not on the molded surface of product.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of TPU film hot briquetting.

Fig. 2 is the operation chart of TPU film heating steps.

Fig. 3 is the operation chart of TPU film and mould engagement step.

Fig. 4 is the operation chart of die venting moulding the fixating shape step of lowering the temperature.

Fig. 5 is for adopting prior art to form the schematic diagram of the steam vent marking on TPU film.

Fig. 6 is the formation schematic diagram in the pore road of mould of the present invention.

Fig. 7 be mould of the present invention exhaust duct schematic diagram is set.

Fig. 8 be mould of the present invention steam vent schematic diagram is set.

Fig. 9 is the modular structural representation of mould of the present invention.

Figure 10 is the view that is cut into finished product of the TPU film after shaping.

Figure 11 is the view of the TPU film finished product made, and a is the TPU film finished product that art methods is made, and b is the TPU film finished product that mould of the present invention and method are made.

Figure 12 is the TPU diaphragm on the keyboard that makes of application the present invention.

Figure 13 is the TPU diaphragm on the keyboard that adopts prior art and make.

The specific embodiment

With specific embodiment, to invention, be described in further detail as follows below:

As shown in Figure 1, the key step of TPU film hot briquetting is:

(1) TPU film is heated to it and becomes glassy state;

(2) the TPU film that is heated to glassy state is engaged with mould;

(3) mould exhaust moulding cooling make the sizing of TPU film;

(4) sizing after the demoulding of TPU film and cut rim charge;

(5) obtain TPU film finished product.

Wherein, as shown in Figure 2, described step (1) is that TPU film 1 is heated to approximately 200 ℃, continues 3-5 second, makes it to become glassy state, prepares to engage with mould 2 simultaneously.As shown in Figure 3, described step (2) is that order is preferably the mould 2 of aluminum alloy material and the TPU film of glassy state 1 is mutual to engaging, form the state that TPU film 1 covers mould 2, and on TPU film 1 several press mold points 5 around, exert pressure, make TPU film 1 and mould 2 recesses form airtight air chamber 3.Wherein, described exerts pressure, and is to adopt the press mold frame (all not shown in figure) being driven by press mold cylinder to exert pressure to several press mold points 5.As shown in Figure 4, in described step (3), after TPU film 1 engages with mould 2, the method of Design of Dies of the prior art is: at the recess of mould 2, offer steam vent 4, after exhaust, make TPU film 1 and mould 2 fit tightly, and make the cooling solidification of TPU film, reach the object of sizing.Wherein, described cooling solidification, rate of temperature fall is preferably controlled at 2.5-4 ℃/s.Described step (4) is after completing the sizing of TPU film, more as shown in figure 10, cutting TPU film rim charge, completes the making of TPU film finished product.Yet, as shown in the finished product schematic appearance of the view of Fig. 5 and Figure 11 a and Figure 13, with above-mentioned existing mold method for designing, carry out the manufacture of TPU film, can cause at finished product in appearance, form the marking 6 of steam vent, logical be called " vacuum eye " in this area.

The present invention makes change arranging of die venting: as shown in Figure 6, when TPU film 1 is heated as glassy state, if its minimum warpage angle is R, and in the making of recess on mould 2, make the angle R1 forming between the inwall of recess and bottom surface, meet R>R1, thereby form pore road 7 between the composition surface of the recess of TPU film 1 and mould 2.Wherein, the width in this pore road 7, that is the gap between TPU film 1 and mould 2, preferably below 0.05mm.Again as shown in Figure 7, in the bottom of each recess 4, be provided with in the horizontal direction many exhaust ducts 8, each pore road 7 be communicated with by each exhaust duct 8, and in mould, form the network of crisscross exhaust duct 8.Again as shown in Figure 8, beyond recess 4, do not affect the position of TPU film finished product outward appearance, the steam vent 4 of the company's of offering vent cap 8 carries out exhaust.When mould 2 cannot or be difficult to obtain by the processing of single module above-mentioned while being exhaust duct 8 that network sample interconnects and steam vent 4, can, in the design of mould, mould be divided into a plurality of modules.As shown in Figure 9, by design, make the module 12 that is positioned at the module 11 of top and is positioned at below after intussusception combination, except forming at faying face necessary exhaust duct 8, the remainder of faying face is mutual fit closely, thereby form mould 2 integral body, steam vent 4 is opened in to the position of the molded surface that does not affect TPU film product simultaneously.Separately as shown in Figure 9, as required, the exhaust duct 8 being interconnected also can have part to be arranged under the bottom surface of described recess.

As shown in figure 10, after completing the sizing of TPU film, cutting TPU film rim charge, produces TPU film finished product, and this finished product does not have the marking forming because of steam vent in appearance, as shown in the view of Figure 11 b.

Wherein a kind of application examples of the present invention is as, the TPU diaphragm that computer keyboard is used, and its outside drawing as shown in figure 12.

Claims (6)

1. the mould of a TPU film, it is characterized in that, on described mould, offer some recesses, the angle R1 forming between the inwall of described each recess and bottom surface is less than the minimum warpage angle R when TPU film is heated as glassy state, make when TPU film engages with mould, due to the differential seat angle of R and R1, at TPU film, form pore road; In the bottom of described each recess, be provided with in the horizontal direction many exhaust ducts, each pore road is communicated with by each exhaust duct, and in described mould, forms the network in pore road; Beyond described each recess and do not affect the position of TPU film finished product outward appearance, offer some and the steam vent for exhaust pore road network-in-dialing.

2. the mould of TPU film as claimed in claim 1, is characterized in that, described mould is divided into a plurality of modules, forms described mould after combination.

3. the mould of TPU film as claimed in claim 1, is characterized in that, described mould is divided into upper and lower two modules, and these two modules are in conjunction with the described mould of rear composition; On the correspondence position of the faying face of these two modules, offer respectively groove, two modules in conjunction with time corresponding groove combination form described exhaust duct.

4. the mould of the TPU film as described in any one in claims 1 to 3, is characterized in that, the width in described pore road is below 0.05mm.

5. a manufacture method for TPU film, is characterized in that, step is as follows:

(1) TPU film is heated to it and becomes glassy state;

(2) the TPU film that is heated to glassy state is engaged with mould;

(3) mould exhaust moulding cooling make the sizing of TPU film;

(4) sizing after the demoulding of TPU film and cut rim charge, obtain TPU film finished product;

Wherein, described mould is the mould of the TPU film described in any one in claims 1 to 3.

6. the manufacture method of TPU film as claimed in claim 5, is characterized in that, the width in described pore road is below 0.05mm.

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