JPS58203018A - Manufacture of thermoplastic resin sheet or film - Google Patents

Abstract

PURPOSE:To obtain the sheet which is unoriented, transparent, excellent in a surface gloss and free from the unevenness in thickness, even though a crystalline thermoplastic resin is its raw material, by introducing the film like thermoplastic resin extruded in a molten state from a T-die to multistep slits in which a cooling water flows. CONSTITUTION:The film like thermoplastic resin 2 extruded in a molten state from a T-die 1 is introduced to a first step slit 3 in which a cooling water flows. The first step slip is shaped in connection with the first water bath 4 positioned under the T-die 1. Here, it is necessary that the water level of the first step slit 3 is made as low as possible. Then, the film form resin is sent to the second step slit 5. The second step slit 5 is shaped in connection with the second water bath 6. Finally, the film form resin is taken up by a take-up roll 10. Thus, the sheet which is unoriented, transparent, excellent in a surface gloss and free from the unevenness in thickness is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing thermoplastic sheets or films.

Conventionally, the chill-roll method and water-cooling method are known as methods for producing thermoplastic resin T-Glue sheets. Thickness unevenness and wrinkles may occur due to poor adhesion between the roll and the molten resin film, and furthermore, in the case of thick sheets, curling may occur due to the difference in cooling between the front and back sides of the molten resin film. There are drawbacks such as a decrease in transparency and surface gloss due to insufficient rapid cooling.In addition, in the water cooling method, heat radiation from the molten resin film occurs locally on the cooling water surface, resulting in cooling failures caused by ripples and shaking of the water surface. Due to lack of uniformity and insufficient cooling, uneven thickness and unevenness or reduction in surface gloss occur, resulting in the disadvantage that high-speed molding cannot be performed.

By the way, the water cooling method has the advantage of being able to cool sheets etc. more efficiently than the roll method. Therefore, as a method to improve the drawbacks of the water cooling method described above, it has been proposed to cool the molten resin film with a flow of cooling water flowing on both sides of the film. However, even with this improved method, properties such as transparency and high-speed moldability of the sheet cannot be fully satisfied. The present inventor has already developed a method for producing thermoplastic resin sheets or films that eliminates these drawbacks. However, as a result of continued research, they discovered a method with even better effects and completed the present invention.

The present invention is a method for producing a thermoplastic voltage sheet or film, which is characterized by introducing a 4 m thick film-like thermoplastic sheet extruded in a molten state from a T-die into a multistage slit through which cooling water flows. .

The thermoplastic sand used as a raw material for sheets and films in the present invention is not particularly limited, and examples include polyolefin (polyethylene, polypropylene, etc.), polystyrene, polyvinyl chloride, etc. Although crystalline thermoplastic resins with problems such as transparency and surface properties (-7) can be used without causing such problems, the sheets and films of the present invention includes multilayer sheets and films (
Even the ones made by JUL (added with smearing agents such as silica, talc, bara-tert-butyl alcohol, aluminum, and dibenzylitensorhitol) are old.

The invention is basically the same as the method for producing thermoplastic resin sheets or films by water cooling. When the molten thermoplastic film extruded from the T-die is introduced into a slit through which cooling water flows, the water level in the slit must be kept as low as possible or the thermoplastic film will not be cooled. It becomes uniform, and it is difficult to obtain a product with excellent transparency and surface gloss.

However, when using multistage slits of two or more stages as in the method of the present invention, it is necessary to set the water level as low as possible for the first stage slit, or for the slits after the second stage. obtained the unexpected finding that even if the water flow is disturbed, the quality of sheets and films is not significantly affected, and there is no need to take special care in adjusting the water level.

However, in the present invention, it is important to consider that the water level of the slit in the first stage is as low as possible. Not considered.

The inventive method will be explained with reference to the drawings. A thermoplastic resin film 2 extruded in a molten state from a T-die 1 is introduced into a first stage slit 3 through which cooling water is flowing. This first stage slit is formed to be connected to the first water slit 4 located below the T-die 1, and usually has a length of 5 to 10 cm.
[ ]Qa or 30 to 50 mouths is preferable.

In the first water dam 4, the cooling water that comes into contact with the cylindrical plasticity of the W person is flowing in the layer 5j shape.
··preferable. Also, the light blue color is “Re-enter S-
Do you want to go to 6? And this, liG, the lung fraction (,
It is possible to prevent damage and increase the number of cooling points. , it is preferable that this water level be below 7 motions. When it comes to 10 or 10 hu here, the obtained sheet has a boiling point of Mt ”;l
+ Haze spots, curl or 2, C haze is also 25-2
8%, which is favorable (8.

Cold water 1 water: Since it is cooled from the water level 4 to the slit 5, it is cooled by the cooling water to the - shaped thermoplastic pipe (rl, forgetting the slit 5). , film-like p-: i, β and the running direction of the cooling water. It is desirable that this cooling water has a speed equal to or thicker than the normal traveling speed of the ligament.

Then, the resin film is sent to the second stage slit 5. This group 2, group slit 5 is located below the first-stage slit 5, and the distance between them I'fj5 is 10 to 200 (1)). The two-stage slit 5 is connected to the second water tank 6, and its length + i = 1 mini one-stage slit (5 to 100 m is appropriate, and preferably 50 to 50 m).

Furthermore, a desired number of 6th stage slits, 5 water buckets, 4th stage slits, 4th water tank, etc. can be provided in a similar arrangement.

Similarly to the first stage slits, the second and subsequent slits are cooled by flowing water along the resin film, and as shown in the figure, new cooling water is added to the second and subsequent water tanks. However, in the tanks after the second tank, the water level of the cooling water is 4! ! There is no need to make an interval. That is, the present inventor has discovered the unexpected fact that at this stage, even if the water flow is disturbed, the quality of the resulting resin sheet or film is not affected.

The film-like resin introduced into the multistage slit through which the cooling water flows as described above and cooled is transferred to the guide roll 7 as shown in FIG.
．． 8, then passes through a draining roll 9 and is taken up by a take-up roll 10, or as shown in FIG. 2, the kite roll 8. Mizukiri Shirole 9
After that, I took delivery of Shiroru 1 [1 Kokoyori 51 and 7]. There are two Kite Rolls 7G, and the - Hitomi Fuki lIβ is located in the center of the slit.

It can also be used as a v and a copy roll to turn the i-ruka roll into a r-j-j.

Regarding the temperature of the cooling water used in the invention (12 to 50"C
range of force) preferably, and if necessary, an interfacial activation oath,
, can be added to milk to make it more wet. figure? , 11 is the lower front - water tank, 12 is the 71 position adjustment plate, 1
14 is a cooler, and 15 is an overflow plate.

In Rumoi above, the cooling of film-like resin using multi-stage slits was shown using the Motoichi type (Swan) 9
1 It is possible to do the same with the tnL type.

The improved water-cooling method of the present invention makes it possible to obtain unoriented sheets with transparency and surface gloss even when producing sheets or films using dark thermoplastic abrasive resin as a raw material. I can do it. Moreover, the obtained sheet etc. has no uneven thickness, wrinkles, curls, etc., and has a uniform 4G strength. Further, the method of the present invention has features such as being able to form sheets etc. by high-speed molding of 1i3 m/mi or more and having low cooling costs.

Since the sheets and films obtained by the method of the present invention have the above-mentioned excellent properties, they are suitable for packaging foods, medicines, etc. Moreover, it can also be used as a raw fabric for C solid phase forming phase such as air pressure forming, roll rolling forming, and stretching forming.

The present invention will now be described by way of examples.

Examples 1 to 6 Polypropylene (density 0.91 flcdt, melt index zOLi-/10 min) was heated to a resin temperature of 28
T-die extrusion device (extruder type 60/, L/D=
28. Die width 550wn, die lip opening 1t
m). The extruded molten resin film is passed through the first stage slit (width 2 days,
After introducing the cooling water (45 tan in length), cooling water (
The second stage slit (4 m wide,
After cooling it, it was introduced into a tube with a length of 10 m) as shown in Fig. 2 (
However, a polypropylene sheet was taken off using a take-off roll (excluding actual 1 second i14.5). Example 4.54m was conducted by adding the conditions shown in the notes column to the two conditions of the prison sentence. The operating conditions and physical properties of the obtained sheet are shown in Table 1.

Comparative Example 1 Table 1 shows the results of the same procedure as in Example 1 except that the two-stage slit was not used.

Comparative Example 2 A film-like resin in a molten axis state was extruded using the same raw materials and extrusion conditions as in Example 1, and a holypropylene sheet was obtained by cooling it by blowing air with an air knife onto a single-sided roll (40'C). Ta. The results are shown in Table 10

[Brief explanation of drawings]

Figure 2 is an explanatory diagram showing a tiller equipped with seven axes of horizontal pressure according to the present invention. 1 T-tie, 2. call ridge cane tokasen (shigo, 5-1 step sui 1 nont, 4...$1 suiden, 5-.72 step slit,
6. Inn 2 Water and Patent Exit'person Idemitsu Seki Chemical Company Representative Person
Patent Attorney Missing Stock 1) Intestine Figure 1 Figure 2

Claims (1)

[Claims] A method for producing a thermoplastic resin sheet or film, in which a film-like thermoplastic resin inserted in a molten state from a T-tie is introduced into multi-stage slits through which cooling water flows.