JPS62267332A - Drawn vinylidene chloride resin film for lamination - Google Patents

Abstract

PURPOSE:To provide a drawn film composed of a specific vinyl chloride copolymer resin, having excellent barrierness to steam and odor, etc., excellent bonding properties and adhesivity to other resins and suitable for lamination. CONSTITUTION:A drawn film having a heat-shrinkage of <=5% in hot water at 80 deg.C and composed of a vinylidene chloride copolymer resin having methyl methacrylate component content of 3-7wt% and containing <=1wt% plasticizer. When the surface roughness of the film is represented by a HAZE value, the HAZE value measured before masking is 1-6% and the difference from the value measured after masking with dibutyl sebacate is 0.5-3%. The film can be manufactured by carrying out the thermal-setting of a film by a contact heating method at a temperature (>=100 deg.C) higher than conventional process, thereby promoting the dissipation of the plasticizer, decreasing the thermal shrinkage and forming a roughened surface.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to a stretched vinylidene chloride resin film, which is made by laminating aluminum foil, paper, and other types of synthetic resin films on the surface thereof, and serves as a rear material. Regarding improved technology.

[Prior art]

・Usually, the core material is a zeta-resistant film, and the surface is laminated with paper, metal foil such as aluminum, tin, and various synthetic resin films represented by various names such as polyethylene, polypropylene, polyester, polyamide, polyvinyl alcohol, etc. Composite films of 20μ to 200μ can be used, for example, in pharmaceuticals, sweets, seasonings, retort foods, etc.
It is widely used as a packaging material for various foods such as frozen foods, processed livestock/fishery foods, and seasoned boiled processed foods.

At this time, when the packaging material itself is required to have both high flexibility and flexibility, the core material should be ethylene vinyl alcohol saponified mfa (fist is engineered, 2-
Currently, resins) are being adopted.

In general, other types of synthetic resins that have high levels of resilience and flexibility include, for example, vinylidene chloride resin (Saran).
Resin) is known, and species of resin cypress 11
When used under conditions where the resin absorbs moisture, the original resin properties can be utilized. Enols, which are said to be incapable of being used, have often appeared as a solution to the drawbacks of resins, and improvements have been considered, but the following drawbacks cause a decline in quality when made into composite films. Currently, it is not used except for extremely limited applications because it is associated with high cost and high costs.

[Problem that the invention seeks to solve]

The m-point of the above vinylidene chloride resin is as follows: (a) In order to ensure the film formability that allows industrial extrusion film formation using the single-layer inflation stretching method, it is necessary to add approximately 2% or more of a plasticizer. However, this amount of addition lowers the anti-reflection properties to a lower level.

(Example) Due to its poor adhesion with other resins, it is difficult to carefully select the adhesive used and the partner resin. There is also a strong tendency for the bonding strength to decrease.

c) Corona treatment and anchor treatment are also carried out on the adhesive interface, but this increases the cost of the resulting packaging material.

etc. In this sense, the purpose of the present invention is to develop a vinylidene chloride-based resin that has excellent gas repellency, excellent bonding and adhesive properties with other resins, and has a quality characteristic level compatible with industrial resins. The object of the present invention is to provide a stretched film for lamination.

[Means for solving problems]

1. Made of vinylidene chloride copolymer resin with a methyl acrylate component of 3-7% by weight and a plasticizer content of 1% by weight or less, the heat shrinkage rate in hot water at 80℃ is 5%.
The following stretched film is used.

(2) Moreover, the surface of the film is uneven, and when the unevenness is expressed as a HAZE value, it was measured before masking) (AZE value is 1% to 6%,
(hereinafter abbreviated as DBS). HA measured after masking
The difference from the ZE value can be expressed as 0.5% to 3%, and is characterized by adopting the above 1.11.

The content of the present invention will be explained in detail below using drawings and the like.

FIG. 1 is a conceptual diagram of an apparatus convenient for producing the stretched film of the present invention.

Using FIG. 1, the method for manufacturing the film of the present invention will be explained first.

In FIG. 1, the resin supplied from the main part 2 of the extruder 1 is propelled by a scrimmer 3, heated, kneaded, and melted, and then transferred to the slit part of an annular die 4 attached to the tip of the extruder. It is extruded to form a cylindrical ξlison 5.・Zorison 5 is approximately 1 with cold water 7 of cooling tank 6 and refrigerant 8 in parison.
It is rapidly cooled to 0°C, guided to pinch rolls A and A' into a cylindrical shape, preheated to about 40°C in hot water tank 9, and then transferred to pinch roller groups B and B'.

c and a', depending on the volume of air sealed in the cylindrical film and the speed ratio between the vinyl rolls B, B', O, and C', approximately 4 in the circumferential direction and longitudinal direction of the cylinder, respectively. Stretched and oriented twice.

The stretched cylindrical film is folded into two flat sheets 11',
12, 12'), and about 100 when tensioned.
℃~130℃, the cooling roller 13.13'
After the film is cooled, both ends of the film are cut open, the film is peeled off one by one, and the film is wound onto winding tubes D and D'. Continuous production is achieved through the above series of continuous operations.

The characteristics of this method are as follows a) and b).

a) The resin to be used in the extruder should contain 3 to 7% by weight of methyl acrylate component, and the content of plasticizer should be adjusted to be slightly higher than the target content when it is made into a film. b) Heating with a heating device is performed at a higher temperature than the heating conditions of conventional heat fixing, that is, at a high temperature of 100°C or more. Therefore, a contact heating method is used in which the film is brought into contact with the heated device surface. to use

The above-mentioned requirements a) and b) are necessary to simultaneously ensure extrusion film formability and ensure the gas/ζ rear level of the final film.

In Figure 2, the scale for the methyl acrylate component 4M% is the dissipation rate of the plasticizer contained (unit weight %), and the horizontal axis is the content of plasticizer initially contained in the resin (unit weight %). There is.

The results shown in Figure 2 show that the plasticizer in the raw resin can be economically dissipated under the extrusion-film-forming-heat treatment process conditions of the present invention, and the amount of residual plasticizer in the final stretched film is reduced. It is shown that.

Next, Figure 3 shows the methyl acrylate component in the resin,
This is a diagram showing the relationship between the level of A and IJ that can be achieved.
The horizontal axis is the amount of methyl acrylate component in the resin, the vertical axis is the amount of oxygen permeation, the broken line is the level of vinylidene chloride resin films currently commercially available in the field, and the one-dot chain line is the level of Epal resin. , each of which is shown as a straight line. The level of oxygen permeation of the film of the present invention indicated by the solid line is as follows:
The illustrations are for a case where the plasticizer content in the resin is 1% by weight and the film thickness is 25 microns.

According to the results shown in Fig. 3, it can be easily guaranteed that the level of .
In order to achieve a value that can match the oxygen permeation level of the resin under %RM environmental conditions, the methyl acrylate component must be at least 7% by weight. The level of plasticizer content can be reached only by reducing the plasticizer content to 1% by weight or less.

In addition, according to the findings of the present inventors through these experiments, when the amount of methyl acrylate component is less than 3% by weight,
It is difficult to form a film by restricting the amount of plasticizer used, so 3% by weight or more is selected.

The technical idea shown in Figures 2 and 3 above is based on a) of the above manufacturing method.
, b) In order to improve the barrier properties of the vinylidene chloride resin (reducing the amount of oxygen permeation), the monomer component copolymerized with vinylidene chloride is 3 to 7% by weight. Vinylidene chloride-based resin, which is methyl acrylate, will be used, but in order to ensure its suitability for extrusion, a large amount of plasticizer (for example, 2% by weight) exceeding 1% is included in the melt extrusion-film forming stage. The plasticizer in the film is efficiently and economically produced by heating it to dissipate the plasticizer in the film during the process, and the amount of plasticizer in the film is reduced to IM amount%. A small amount of the following, preferably in an unplasticized state, ensures ζ rear properties. This completes the film of the present invention.

In other words, in feature b) of the manufacturing method, the heat treatment performed under tense conditions not only promotes the above-mentioned plasticizer dissipation phenomenon, but also reduces the heat shrinkage rate of the film to less than 5!6. Trim the film into a stretched film. Furthermore, it plays the role of causing unevenness on the film surface itself. For this reason, we propose that it is more advantageous to set the heating conditions to a higher temperature than conventional ones, that is, to a temperature of 100° C. or higher, and to employ contact heating.

Next, the reason why it is a stretched film is that it is used as the core material of the final composite film to give the composite film mechanical properties such as stiffness, tensile strength, and tear strength. be.

In addition, even though it is a stretched film, the heat shrinkage rate measured in 80°C hot water must be 5% or less, which is important for the adhesion between the core film and the surface film after it is made into a composite film. , is a constraint requirement to make it stronger. Therefore, the smaller the heat shrinkage rate, the more advantageous it becomes.

Next, the HAZE value measured with the film as is and the HA value measured after applying DBS masking to the film.
The characteristic shown by the combination of the two values, including the difference in ZE value, indicates the unevenness of the surface of the film and controls the improvement of bondability with other types of films.

That is, the surface condition of a commercially available vinylidene chloride resin film is smooth and corresponds to the value after the DBS masking described herein.

When masking is performed using Tsumasu DBS, it corresponds to when the state is restored to a smooth state. Therefore, in the present invention, each of the HAZE value before masking and the difference between the HAZE values before and after masking can be said to be an index indicating the state of the unevenness of the film.

Therefore, the value before masking shown in this combination is the sum of the original value of the resin and the value due to film unevenness caused by heat treatment, and is not classified as foaming whitening due to moisture etc. in the resin. Ru. Immediate value [HAZ before masking]
E value, (HAZB value before masking and after masking)
(difference from AZE value)], if the value is larger than [6%, 3%], the role of the relative insulating effect in laminating with the surface film increases, but the composite film This will worsen the transparency and surface condition of the composite film after the film has been bonded to the surface film.On the other hand, if the value is smaller than [1%, 0.5%], the effect will be too small and the bonding with the surface film will deteriorate. Difficult to demonstrate effectiveness. Therefore, in practice, the value before masking is 1% to 6%, and the difference value before and after masking is 0.
It is desirable to select from within the range of 5% to 3%.

The bonding effect of such an uneven surface improves the bondability, and whether using an adhesive or heat welding, the degree of freedom in selecting a partner increases, and the bonding tension also increases.

In the present invention, the vinylidene chloride resin containing 3 to 7% by weight of methyl acrylate component is a vinylidene chloride-methyl acrylate copolymer with a
(based on the GPO method) is in the range of 70,000 to 250,000, and the ratio to the number average molecular weight determined by the same GPO method (i.e., weight average molecular weight ÷ number average molecular weight) is in the range of 2.0 to 3.0. desirable. More preferably, the weight average molecular weight is in the range of 80,000 to 130,000, and the ratio to the number average molecular weight (weight average molecular weight/number average molecular weight) is in the range of 2.0 to 2.4.

The weight average molecular weight and number average molecular weight referred to here are values determined by the method described in Japanese Patent Publication No. 59-240483, that is, the GPO (gel emission chromatography) method.

The plasticizer used in the present invention refers to a liquid plasticizer known as a plasticizer for vinyl chloride resin. Among them, from the viewpoint of food safety and hygiene, liquid plasticizers are carefully selected from aliphatic dibasic acid esters, citric acid esters, fatty acid esters, polyesters, etc., and preferably diisobutyl adipate, diisobutyl adipate,
These include dizotyl setinate and tributyl acetyl citrate.

More preferably, the above plasticizer and diynbutyl adipate are used in combination (for example, if the diisobutyl adipate component is
0% by weight or more) is desirable.

Qualitative and quantitative information on plasticizers can be found in publications related to analysis, such as "Polymer Analysis Book" (Japan Society for Analytical Chemistry Network 1985).
It can be carried out using a gas chromatograph and a mass spectrometer according to the solvent extraction method described in 2010).

The plasticizer dissipation rate is the ratio (wt%) of the plasticizer amount (B) dissipated during the extrusion-film forming process to the initial content (wt%), that is, the plasticizer dissipation rate (wt%) = - The amount of plasticizer (% by weight) in the X100 raw material resin.

The evaluation method and evaluation scale used in the present invention are shown below.

a) Oxygen gas transmission rate (OTR) Based on ASTM D3985 [Unit CC/m” ・24 Hr-aim at 20
°C) Evaluation scale evaluation symbol Standard value ◎; Less than 2 CC Q; 2 CC or more - less than 5 CC Δ; 5 CC or more - less than 10 CC The average value of

Evaluation scale evaluation symbol Standard value ◎; Less than 1% ○; 1% or more - less than 5% △; 5% or more - less than 10% ×; 10% or more c) HAZE ASTM-D10Q3 compliant <before masking> - After shaking and washing in hexane for about 3 seconds,
It is measured after being adjusted for 24 hours in a testing room at ℃±2℃ and 65% RH±5% RH. This value is the value before masking (
A%).

<Masking/Difference before and after> Next, using the same test piece as described above, masking is performed by applying DBS on both sides of the test piece using a wire rod or the like, and measurement is performed after 5 minutes. This value is defined as the value after masking (B%). The HAZE value (loading % - B%) % at this time is taken as the value of the difference between before and after masking of the test piece.

After lamination〉 Measured without cleaning (n-hexane) pretreatment [Unit: %] Evaluation scale evaluation symbol Standard value ◎; 10% undropped ○; 10% on-site ~ less than 15% 61 15% or more ~ less than 20% × ; 20% or more d) Water vapor transmission rate ASTM-F372 compliant [unit? /m” 24) 1r at 40℃90%
RH] Evaluation scale evaluation symbol Standard value ◎; Less than 22 ○; 29 or more ~ 5? Less than Δ; 52 or more to less than 1ot x; ior or more e) Tensile breaking strength.

A8TM-D882 compliant 〔unit ! /97α2] The average value of vertical and horizontal values was rough.

Evaluation scale rating symbol Standard value ◎; 1000 words or more ○; 7QQ person 1 or more - less than 10004 △; 400
More than 700 to less than 9 ×; less than 9 to 400 f) Tensile modulus (apparent modulus at 2% elongation) AST
Based on M-D882 [Units! 4/儒2〕 Evaluation scale evaluation symbol based on the vertical and horizontal average values Standard value ◎; 10,00014 or more ○; 7,00 (11 or more to less than 10,000 'Δ; 3,00OA9 or more to 7, Less than 000ApX; less than 3,000kg ] Evaluation scale evaluation symbol with average value of vertical and horizontal values Standard value ◎; 6r or more ○; 4? Above ~ 6P not yet, 9 ×: 2? Less than h) Thickness based on ASTM-D374 [unit: μ] i) Laminating strength A laminate film was created using a P-ly laminator based on ASTM-D and 1876 (conditions etc. are shown below). After aging the obtained laminate film at 40° C. for 2 days and then at room temperature for 14 days, the lamination strength with the 0-Nylon film was measured, and the value was taken as the lamination strength.

[Unit: P/15Tr! R width〕〈Lamination conditions〉 (Substrate film) ・Rear single-layer film; Wooden invention product; Saran ■Film 015M; Kurehalon ■Film Keiflex surface layer film: ONylon CRT type 15μ, Unitika Co., Ltd.
(Made by Mechanical Conditions, etc.) Speed: 80 m/min Nip roll; 75°C Drying; 70-75°C Coating method; Gravure coat evaluation scale evaluation symbol Standard value ◎; 500f or more ○; 400°C or more - less than 5002 Δ; 20
05' or more to less than 4002 In addition, the base resin used in the following experimental examples and examples has a ratio of vinylidene chloride component and methyl acrylate component of 97:3 [vinylidene chloride (wt%)]
; methyl acrylate (weight%), the same below], 96:4
, 95:5, 93 near, and 90:10, and 1.0% by weight of epoxidized linseed oil was added as a heat stabilizer to each of the vinylidene chloride-based resins.

This base resin can be produced by the method described in % Application No. 59-240483.

Experimental Example 1 Diisobutyl adipate and tributyl acetyl citrate (both plasticizers) were added to the base resin whose component ratio of vinylidene chloride component and methyl acrylate component was 96:4.
A mixture of (diynbutyl adipate 70% by weight; tributyl acetyl citrate 30% by weight) was added and mixed in amounts of 1%, 2%, and 3% by weight to obtain three types of resins. These resins were extruded and
Form a film and roll it into a bin at a winding speed of 30 m/min, width 10
00 rrm and a thickness of 15 microns was obtained.

The length of the heating furnace 10 at this time is approximately 7 m, and the temperature inside the furnace is 100 m.
℃, the temperature of heating roller 11.11' is 120℃
The temperature of the heating rollers 12 and 12' was 130°C.

For the three types of films obtained, the amount of plasticizer remaining in the film was measured, and the plasticizer dissipation rate (% by weight) was determined.

The results are shown in Figure 2.

The results shown in Figure 2 indicate that the vinylidene chloride resin composition of the present invention has the characteristic that about half of the initially contained plasticizer is dissipated during the extrusion, film forming, and heat treatment steps. There is.

Experimental Example 2 The component ratio of the vinylidene salt component and the methyl acrylate component is 97; 3, 95; 5, 93; 7, 90; 1
0 was selected, the plasticizer used in Experimental Example 1 was added, and four types of films with a thickness of 25 microns were obtained in the same manner as in Experimental Example 1.

The amount of residual plasticizer in these films corresponds to approximately IM amount %.

The amount of oxygen gas permeation was measured for these four types of films.

Figure 3 summarizes the results and shows the level and process of vinylidene chloride resin films currently on the market in the electroplating field.
It is a diagram that also shows the level of resin.

The results shown in Figure 3 show that in order to achieve a value comparable to the level of oxygen permeation shown by Epal resin, the methyl acrylate component must be at least 7% by weight or less, and the plasticizer content must be increased to IM. This indicates the need to keep the amount below %. Further, according to the knowledge obtained through these experiments, when the amount of the methyl acrylate component is less than 3% by weight, film forming properties become difficult. From this, it is necessary to select a methyl acrylate component amount of 1% or more by weight.

Example 1 0.7% by weight of diisobutyl adipate and 0.3% by weight of acetyl tributyl citrate were added to the base resin in which the component ratio of the vinylidene chloride component and the methyl acrylate component was 96:4.
A weight of 9G (all liquid plasticizers) was added and mixed. Using this resin, compared to the extrusion film forming method described in Example 1,
The processing temperature in the heating furnace was 120°C, and the heating roller 11.
The treatment temperature at 11' was 130°C, heating roller 12.1
Under the same extrusion film forming method conditions as in Experimental Example 1, except that the treatment temperature at 2' was changed to 140°C,
000 mm and a thickness of 15 microns.

The amount of residual plasticizer in the obtained film was 0.6% by weight.

This film was evaluated on the 11 items (laminate suitability evaluation items) described in the text. For comparison, Saran Film 015M [trade name, manufactured by Asahi Kasei Corporation],
Krehalon Film K-Flex [trade name, manufactured by Kureha Chemical Co., Ltd.] was also evaluated at the same time.

The results are summarized in Table 1.

From the results in Table 1, it can be seen that the film of the present invention is superior to conventional laminating films in the following points.

・・High adhesiveness with other types of films (laminate strength) ・High elastic modulus (sharp elasticity) Also, film strength (breaking strength, tearing strength) is low. Heat deformability (low heat shrinkage), transparency after lamination (low H
It can be seen that the AZE value (AZE value) also maintains the standard value of the conventional product difference.

[Effects of the present invention]

By virtue of having the above-described structure, the present invention has excellent resistance to water vapor, smell, oxygen, etc., at least compared to vinylidene chloride resin films on the market, and has excellent resistance to water vapor, smell, oxygen, etc., and is resistant to bonding and adhesion with other resins. It can be said that this invention is an excellent invention that can provide a stretched vinylidene chloride resin film for lamination with quality properties comparable to Ninoru resin, which has excellent properties.

Margin below

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a stretched film manufacturing apparatus of the present invention. FIGS. 2 and 3 are experimental diagrams for explaining the technical content of the present invention, and are characteristic diagrams showing the usefulness of the obtained films. 1... Extruder, 10... Heating furnace, 11, 11',
12, 12'... heating roller, 13.13'.
- Cooling roller, D... Winding Zebin Patent applicant Asahi Kasei Industries, Ltd. Figure 3 MA slope ratio in copolymer (weight %) Procedural amendment January 7, 1986 Commissioner of the Patent Office Black 1) Akio Tono 1 Incident Display 1986 Patent Application No. 11064
6 No. 2, Name of the invention Vinylidene chloride resin stretched film for lamination 3, Relationship to the case of the person making the amendment Patent applicant: 1-2-6 Dojimahama, Kita-ku, Osaka, Osaka, Japan (003)
Asahi Kasei Corporation 4, “Claims” and “Detailed Description of the Invention” of the specification subject to amendment
Column 5, Contents of amendment (1) The "Claims" on page 1 of the specification will be amended as shown in the attached sheet. (2) On page 2, lines 9-10, 1-Ame sweets, etc.'' is corrected to ``Lome confectioneries,''. (3) Correct "oscillability" in line 14 of page 2 to "flexibility". (4) “Promoted with Screamer 3” on page 5, line 8 of the same page.
is corrected to "propelled by screw 3." (5) "Arise" on page 9, line 12 is amended to "Arise". (6) On page 12, line 14 of the same page, amend ``The value is the value determined by.'' to ``The value is the polystyrene equivalent value determined by.'' (7) On page 15, line 9, “with a wire swab, etc.” was changed to “with a cotton swab, etc.”
Correct to. (8) Amend "(覦チ") to "(A-chi") on page 15, line 11 of the same page. (9) Amend FIG. 3 to "FIG. 3" with the accompanying text. range

Claims (1)

[Scope of Claims] The methyl acrylate component is 3 to 7% by weight, and the content of the plasticizer is 1% by weight or less. A stretched film made of a vinylidene chloride copolymer resin and having a heat shrinkage rate of 5% or less in hot water at 80°C,
When the uneven state of the film surface is expressed as a HAZE value, the HAZE value measured before masking can be expressed as 1% to 6%, and the difference from the HAZE value measured after masking with dibutyl sebatate can be expressed as 0.5 to 3%. Vinylidene chloride resin stretched film for lamination, characterized by having surface irregularities