JPS5833102B2 - Sekisoutai no Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A laminate made by extrusion coating a polyolefin resin on a polypropylene fiber fabric (hereinafter referred to as PP cloth) has the advantages of being strong and moisture-proof, as well as being lightweight, so it is particularly popular for heavy use. Widely used for packaging.

Currently, low-density polyethylene (hereinafter referred to as LDPE) is used for PP cloth.
When extrusion coating the PP cloth and the melt-extruded LDPE film, pretreatment such as applying an anchoring agent to the PP cloth is performed in advance to ensure sufficient adhesion between the PP cloth and the melt-extruded LDPE film. The applied PP cloth is extrusion coated with LDPE at a high temperature of about 330°C.

As described above, the conventional extrusion coating method requires a pretreatment process, which not only complicates the work process and increases the manufacturing cost of the laminate, but also causes thermal deterioration of the PP cloth because it is processed at a high temperature of approximately 330°C. However, there is a drawback that the mechanical strength of the laminate is significantly reduced.

In addition, in place of the above-mentioned LDPE, ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) with good heat-sealability is used as PP.
Extrusion-coated cloth also does not have sufficient adhesive strength, so a pretreatment step is required in the same way as in the above case.

The present invention relates to a method for producing a laminate that eliminates the above-mentioned drawbacks, and enables extrusion coating of LDPE, EVA, or a mixture thereof without pretreatment such as anchor treatment on PP cloth. A method for manufacturing a laminate is provided.

That is, the method for manufacturing the laminate according to the present invention uses LDPE or EV.
A or a mixture of both and an ethylene-ethyl acrylate copolymer (hereinafter referred to as EEA) are coextruded into a molten composite film, and the composite film is laminated by pressure on a PP cloth using the EEA side of the composite film as an adhesive layer. It is characterized by

Since the EEA used as the adhesive layer in the present invention has good adhesion to PP cloth when melt-extruded, it is conceivable to extrusion coat the PP cloth alone with EEA, but the EEA layer is It has the disadvantage of poor removability.

However, in the present invention, this drawback is solved by providing an EVA layer or an LDPE layer on the EEA layer.

In the present invention, EEA means a melt index of 1 to 25 at 190°C. ! ii'/10 minutes, ethylene content is 7
0 to 90 weight φ, preferably 75 to 85 weight φ.

In the EEA of the present invention, if the ethylene content exceeds 90% by weight, it will not function as an adhesive layer, whereas if it is less than 70% by weight, it will be difficult to process the coextrusion coating.

As EVA, the melt index at 190°C is 1.
5-40g/10 minutes, preferably 2-30. ! il'/
For 10 minutes, use a rice cake with an ethylene content of 60 to 95 weight, preferably 65 to 92 weight.

This is because if the ethylene content of EVA exceeds 95% by weight, the flexibility and heat-sealability will decrease, and if the ethylene content is less than 60% by weight, coextrusion coating processing will become difficult.

Furthermore, the LDPE of the present invention has a melt index of 1 to 20 g/10 minutes at 190°C, preferably 3 to ICB.
1! /10 minutes is appropriate.

In the present invention, the melt index of EEA, EVA, and LDPE is regulated within the above range, but this is because if the melt index falls outside of the above range, the workability of the coextrusion coating process will be extremely poor, so it is difficult to put it into practical use. This is because it becomes Tanashi.

According to the method of the present invention, EEA as an adhesive layer and LDPE or EVA as an upper coating layer are introduced into a die connector at different processing temperatures from separate extruders, and are melted into a composite film form through a slit in the die connector. Extruded.

At this time, the processing temperature for EEA should be between 280 and 30 degrees, taking into account the adhesive strength with the PP cloth and the thermal deterioration of the PP cloth.
It is appropriate to set the processing temperature to 00℃, and the processing temperature for EVA is 200 to 240℃, and that for LDPE is 250 to 250℃.
It is appropriate to set the temperature to 300°C.

The coextruded composite film is then pressure laminated to the PP cloth using the EEA side as an adhesive layer.

Here, the PP cloth includes polypropylene flat yarn fabrics, split yarn fabrics, and the like.

The present invention will be described in detail below with reference to the drawings.

Example 1 From the first extruder, NUC-8008 (1) (LDPE manufactured by Nippon Unicar Co., Ltd.: Melt index at 190°C 5.0 g/l 0 minutes, density 0.917 g7cr
tt> was extruded at an extrusion temperature of 300°C, and at the same time, DPDJ-6169 (2) (manufactured by Nippon Unicar Co., Ltd. EEA: melt index at 190°C 6.0 g/10 minutes, ethylene content 80% by weight) at an extrusion temperature of 300°C, and as shown in FIG.
700m7IL width, single manifold type die)
A molten two-layer film 5 of LDPE and EEA is extruded from the molten film 5, and the molten film 5 is made into a commercially available PP flat yarn fabric 6 (1000 d).

12 x 12 rolls/in) with a nip roll consisting of a silicone rubber-lined pressure roll 7 and an internal water-cooled metal cooling roll 8, and rolled up at a processing speed of 50 m/min to obtain a laminate 10.

Note that 9 is a guide roll.

Example 2 NUC-8008 (1) was extruded from the first extruder at a temperature of 28
Extrusion at 0°C, DPDJ-61, 82 (
2) (EEA manufactured by Nippon Unicar Co., Ltd.: melt index 1.5 g/l 0 min at 190°C, ethylene content 85% by weight) was extruded at an extrusion temperature of 300'C to produce a laminate according to Example 1. Got 10.

Example 3 NUC-so O9 (1) (LDPE manufactured by Nippon Unicar Co., Ltd.: melt index l/10 min at 190°C, density 0917 g/crtt) was extruded from the first extruder at an extrusion temperature of 270°C, DPDJ-9 from the second extruder
169(2) (Nippon Unicar C Co., Ltd.) EEA: 190°C
Melt index 20? A laminate 10 was obtained in the same manner as in Example 1 by extruding a 280°C extrusion temperature for 10 minutes and an ethylene content of 80% by weight.

Example 4 From the first extruder, NUC-8450 (1) (EVA manufactured by Nippon Unicar Co., Ltd.; melt index at 190°C 2.
! l/10 minutes, ethylene content 85 weight φ) was extruded at an extrusion temperature of 240°C, and DPDJ-9169 was extruded from the second extruder.
was extruded at an extrusion temperature of 280°C to obtain laminate 1 according to Example 1.
I got 0.

Comparative Example 1 A PP flat yarn fabric (1000 d
.

NUC-8008 was extrusion coated at an extrusion temperature of 320° C. to obtain a laminate.

Comparative Example 2 PP flat yarn fabric (1000d,
NUC-8450 was extrusion coated onto 12×12 pieces/in) at an extrusion temperature of 240° C. to obtain a laminate.

Example 3: PP flat yarn fabric (1000 d) treated with NUC-8008 as an anchoring agent using a conventional method.

A laminate was obtained by extrusion coating onto 12×12 pieces/in) at an extrusion temperature of 330'C.

The anchor umbrella* agent is TP manufactured by Toyo Soda Co., Ltd.
A three-way toluene solution of ST-31 (organotitanium compound) was used.

Comparative Example 4 A laminate was obtained in exactly the same manner as Comparative Example 3 except that the extrusion temperature was lowered to 300°C.

Comparison fII5 Adhesive layer from DPDJ-6169 (EEA) to NUC-8
A laminate was obtained in exactly the same manner as in Example 1 except that 450 (EVA) was used.

Table 1 shows the manufacturing conditions and physical properties of the laminates obtained in Examples 1 to 4 and Comparative Examples 1 to 5 above.

In the table, the thickness of the coating film was calculated using the following formula.

The adhesive strength was determined by pulling a sample piece with a width of 25 m at a pulling speed of 300 m.
The strength when peeled off at 7 IL/min and at an angle of 900 was measured using an Autograph manufactured by Shimadzu Corporation.

The lowest seal temperature was determined using a test heat sealer manufactured by Toyo Tester Co., Ltd., with a constant sealing pressure of 1.0 ky/d1 and a constant sealing time of 2.0 seconds, and a sealing temperature of 1008C.
to 200°C at 5°C intervals, the coated film surfaces were sealed together, and the lowest temperature at which sealing was obtained was determined.

The seal strength was determined by pulling a sample piece with a width of 15 m and 11 L at a pulling speed of 3.
The seal strength when peeled off at 00 mw for 1 minute at an angle of 90° was measured using an Autograph manufactured by Shimadzu Corporation.

The strength of the laminate is determined by pulling a sample piece with a width of 25 mπ at a speed of 500
The tensile strength when tensile and sheared at mrn/min was measured using an Autograph manufactured by Shimadzu Corporation.

As is clear from the results in Table 1, LDPE was applied to PP cloth.
When extrusion coated alone, the adhesive strength of the laminate is very weak.

In addition, LDP was applied to PP cloth pretreated with an anchoring agent.
The laminate obtained by extrusion coating E at high temperature has good adhesion but has considerably weak mechanical strength.

Furthermore, a laminate obtained by extrusion coating PP cloth with EVA alone has poor adhesive strength and cannot be put to practical use.

Compared to these, the laminate processed according to the present invention has good adhesion, and has excellent properties such as flexibility, heat sealability, and mechanical strength.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing the coextrusion coating method according to the present invention, and FIG. 2 is a cross-sectional view of a processed laminate. 1... LDPE or EV extruded from the first extruder
A, 2...EEA13 extruded from the second extruder...
・Connector, 4... Extrusion coating die, 5...
- Molten two-layer film, 6... PP cloth, I... Pressure roll, 8... Cooling roll, 9... Guide roll, 10... Coated laminate.

Claims (1)

[Claims] 1. Coextrude low-density polyethylene or ethylene-vinyl acetate copolymer, or a mixture of both, and ethylene-ethyl acrylate copolymer into a molten composite film, and use the ethylene-ethyl acrylate copolymer side of the composite film as an adhesive layer. A method for producing a laminate, characterized in that the composite film is pressure laminated on a polypropylene fiber fabric.