Producing apparatus of film with through-holes

Details Producing apparatus of film with through-holes Producing apparatus of film with through-holes

1998-10-07

2001-10-02

Nguyen, Nam (Department: 1722)

Plastic article or earthenware shaping or treating: apparatus

Preform severing means

Severing means is perforator

C425S324100, C425S335000, C425S363000, C425S471000

Reexamination Certificate

active

06296469

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a producing apparatus and a producing method of a film with through-holes.
In order to make a thin film (for example, 0.03 to 0.08 mm in thick) with through-holes, a stretching apparatus and a punching apparatus are generally used. A thicker plastic film is heated and stretched to a target thickness by means of a stretching apparatus. Then, through-holes are punched in the plastic film by means of the punching apparatus.
However, since separate two apparatus (that is, the stretching apparatus and the punching apparatus) are needed, the whole equipment for producing the film with through-holes is complicated. Further, since the conventional producing method necessities separate two processes (that is, the stretching process and the punching process), the whole process for producing the film with through-holes is complicated.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to simplify the whole equipment and whole process for producing the film with through-holes.
According to an aspect of the present invention, there is provided a producing apparatus of a film with through-holes including (1) a pair of stretching rollers which sandwich a film therebetween and stretch the film, and (2) a pair of punching rollers at least one of which has projections formed on an outer surface thereof, which sandwich the film therebetween and punch through-holes in the film. The stretching rollers and the punching rollers are disposed so that the film stretched by the stretching rollers are fed into the punching rollers.
With such an arrangement, since the stretching of the film and the punching of the through-holes are performed by substantially one apparatus, the whole equipment for producing the film with through-holes becomes simple.
In a particular arrangement, the film is made of shape memory resin. The producing apparatus further includes a first heater which heats the film to a temperature above the shape providing temperature. Above the shape providing temperature, the shape memory resin exhibits a fluidized state. Thus, the film is easily deformed by the stretching rollers. It is preferred that the first heater is mounted in at least one of the stretching rollers.
Further, the producing apparatus includes a second heater which heats the film to a temperature above the glass transition temperature. Above the glass transition temperature (but below the shape providing temperature), the shape memory resin exhibits a rubber state (that is, an elastic state). Thus, the through-holes can easily be formed in the film. It is preferred that the second heater is mounted in at least one of the punching rollers.
Optionally, the producing apparatus further includes a cooling device provided between the punching rollers and the stretching rollers. The cooling device cools the film to a temperature below the shape providing temperature.
In a preferred embodiment, there is provided a method for producing a film with through-holes using the above-described producing apparatus. The method includes the steps of (1) stretching the film by means of the stretching rollers, and (2) punching through-holes in the film in a state the film is stretched.
With such a method, since the since the stretching of the film and the punching of the through-holes are performed in substantially one continuous process, the whole process of producing the film with through-holes becomes simple.
In case the film is made of shape memory resin, the film is heated to a temperature above a shape providing temperature of the shape memory resin, in the stretching step. Further, the film is heated to a temperature above a glass transition temperature of the shape memory resin in the punching step. It is also possible to cool the film below a shape providing temperature of the shape memory resin, after the stretching step.


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patent: 5305666 (1993-11-01), None
patent: 8-49960 (1996-02-01), None
An English language abstract of JP 5-305666.
An English language abstract of JP 8-49960.

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