JP2946691B2 - Manufacturing method of laminated polyester film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a heat-adhesive laminated polyester film having improved slipperiness and workability.

[Prior Art] Conventionally, as a method for imparting thermal adhesiveness to a polyester film, a method has been proposed in which an amorphous layer is formed by laminating a copolymerized polyester, melting it once in a heat treatment step, and quenching it. However, since the slipperiness of the film is reduced in this case, it has been proposed to make the inert particles thicker than the lamination thickness (for example,
[Problems to be Solved by the Invention] However, when particles having a large average particle diameter are added, there are problems such as a decrease in transparency and a decrease in thermal adhesiveness. However, there are still insufficient points as the improvement effect.

An object of the present invention is to provide a method for producing a laminated polyester film having both excellent thermal adhesiveness and slipperiness.

[Means for Solving the Problems] That is, the method for producing a laminated polyester film of the present invention comprises: [A] a layer made of thermoplastic polyester A;
The [B] layer composed of polyester B having a melting point lower than that of polyester A by 10 ° C. or more and the [C] layer composed of water-dispersible and / or water-soluble polyester C containing inert particles are at least [A] / [ B] / [C], and [A] / [B] at the time of melt extrusion.

The polyester A referred to in the present invention is a thermoplastic polyester comprising an aromatic dicarboxylic acid and an aliphatic glycol, specifically, resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6 naphthalene carboxylate and the like. Is a blend or copolymer. In the present invention, it is particularly preferred that 80 mol% or more, more preferably 85 to 95 mol%, of polyethylene terephthalate is ethylene terephthalate. Here, the polyester A preferably has a crystal melting energy (ΔHu) of 5 cal / g or more from the viewpoint of durability against a thermal load applied during processing.

Next, in the present invention, the melting point is higher than that of polyester A.
The polyester B lower by 10 ° C. or more has an ester repeating unit composed of an aromatic and / or aliphatic dicarboxylic acid and an aliphatic and / or alicyclic glycol as a main skeleton.

Particularly terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, azelaic acid, at least one dicarboxylic acid selected from sebacic acid and ethylene glycol, 1,4 butanediol, diethylene glycol, neopentyl glycol, 1, It is preferable that it comprises at least one alcohol component selected from 4-cyclohexanedimethanol. Further, poly ε-caprolactone and polyoxyalkylene glycol may be copolymerized in a block shape.

Further, polyester B preferably has a ΔHu in the range of 0.1 to 4 cal / g, more preferably 0.5 to 3 cal / g, from the viewpoint of improving the heat sealability.

Further, the difference in melting point between the polyester A and the polyester B is preferably 20 to 60 ° C, more preferably 20 to 50 ° C, in order to improve the adhesiveness. From the same viewpoint, the glass transition temperature of the polyester B is preferably from 45 to 70 ° C, more preferably from 50 to 65 ° C.

The thickness of the layer [B] is preferably from 1 to 15 µm, more preferably from 2 to 8 µm, in order to improve the heat sheet property.

Inert particles may be added to the layer [B]. The average particle diameter is usually 0.1 to 10 μm, and the addition amount is preferably 0.05% by weight because heat sealing properties are not impaired. Here, examples of the inert particles include inorganic particles such as silicon dioxide, alumina particles, calcium carbonate particles, barium sulfate particles, and silicon carbide, and particles such as crosslinked polystyrene particles and silicone particles.

Next, the water-dispersible and / or water-soluble polyester C is a polyester that is dispersed and / or soluble in water or hot water, and has an aromatic polyester as a main skeleton.
It is preferable that the structure contains a sulfonate group and / or a polyalkylene glycol bonded to an ester-forming aromatic ring as its polyester segment. Here, the sulfonate group bonded to the ester-forming aromatic ring is a sulfonate group exemplified by 5 sodium sulfoisophthalic acid, 5 sodium sulfoterephthalic acid, 5 sodium sulfo 2, 7 naphthalenedicarboxylic acid, and the like, Examples of the ion that binds to the sulfonate group include alkali metals such as potassium, lithium, and cesium in addition to sodium. The copolymerization amount is 3 to 20 mol%
Is preferably within the range. Examples of the polyoxyalkylene glycol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. The molecular weight is in the range of 1,000 to 10,000, and the copolymerization amount is 1 to 50% by weight, preferably 5 to 30% by weight. It is preferably in the range of weight%.

Next, the average particle size of the inert particles contained in the [C] amount is preferably 0.01 to 5 μm, and more preferably 0.1 to 3 μm. Further, the addition amount is preferably 0.1 to 50% by weight with respect to the resin of the layer [C] in order to achieve both the slipperiness and heat sealability, and more preferably 1 to 40% by weight. Here, the inert particles are at least one selected from those exemplified above.

The [A] layer, [B] layer and / or [C] layer may contain known antioxidants, heat stabilizers, antistatic agents, weathering agents, flame retardants, UV rays, and the like, as long as the purpose is not adversely affected. An absorbent, a lubricant, a crystal nucleating agent, and the like may be added. Thus, examples of the antioxidant include hindered phenol-based additives such as Irganox 1010 and BHT, and examples of the antistatic agent include metal salts of alkyl benzene sulfonic acid and metal salts of alkyl sulfonic acid.

Further, in the present invention, a [D] layer composed of a metal and / or metal oxide deposited layer may be further laminated, and in this case, the lamination structure is [D] / [A] / [B] / [C] or [ D] / [C] / [A] / [B] / [C].
Here, the metal and / or metal oxide deposited layer [D]
Aluminum, zinc, cobalt, copper, tin, indium,
A single composition, an alloy, or a mixture selected from titanium, silicon, and a compound containing these oxides or a small amount of hydroxide. Particularly, in the present invention, aluminum,
Preference is given to tin, silicon and / or their oxides. [D] The layer thickness is preferably in the range of 10 to 1000 °.

Next, a typical embodiment of a film manufacturing method according to the present invention will be described.

Inert particles are added to the polyester A and the polyester B as necessary, and the resulting mixture is melt-extruded using separate extruders, and laminated in a die manifold section or a polymer tube entering the die.

As described above, a laminate having the laminated [A] / [B] layer as a basic invention is melt-extruded into a sheet or a cylinder, and rapidly cooled and cast to a temperature equal to or lower than the glass transition temperature of polyester A. The cast film thus obtained is uniaxially stretched at a temperature equal to or higher than the glass transition temperature of polyester A to obtain a uniaxially stretched film. The stretching ratio is preferably in the range of 2 to 5 times in the uniaxial direction. Next, the surface of the [B] layer of the uniaxially stretched film is subjected to a corona discharge treatment to obtain an aqueous dispersion containing polyester C and necessary inert particles and / or
Alternatively, it is coated with an aqueous solution, guided to a stenter, dried and stretched in the width direction. It is preferable that the stretching ratio is in the range of 2 to 5 times because both mechanical properties and flatness are improved.

Next, the stretched film is heat-treated at a temperature not lower than the melting point (Tmb) of the polyester B and not higher than the melting point (Tma) of the polyester A, and rapidly cooled and wound.

The film obtained as above can be used as needed.
Surface treatment such as corona discharge treatment, low-temperature plasma treatment, and flame treatment, and the above-mentioned coating treatment can be performed.

[Effects and Uses of the Invention] The polyester film obtained by the production method according to the present invention includes an [A] layer made of thermoplastic polyester A,
At least [A] / [B] a [B] layer made of polyester B having a melting point lower than that of polyester A by 10 ° C. or more and a [C] layer made of water-dispersible and / or water-soluble polyester C containing inert particles. ] / [C], the laminated polyester film has the following effects and uses.

 Excellent heat sealability and lubricity.

[A] When the layer is used after being vapor-deposited, the gas barrier property is excellent because there is no occurrence of blocking or the like.

In particular, when a bag is formed and used, the dropping strength and the gas barrier property are good, and the characteristics can be sufficiently exhibited.

The laminated constitution of [A] / [B], particularly of the laminated polyester film having such excellent properties, can be easily achieved by lamination during melt extrusion.

[Method for Evaluating Characteristics and Method for Evaluating Effects] Evaluation and measurement of effects used in the present invention will be summarized below.

(1) Melting energy (ΔHu), melting point (Tm), glass transition temperature (Tg) Determined using a differential scanning calorimeter DSC2 (manufactured by PerkinElmer).

The measurement was performed at 280 ° C x 5 using a 10 mg sample under a nitrogen stream.
Hold for 1 minute, then quench in liquid nitrogen.

When the sample thus obtained was heated at a rate of 10 ° C./min, a comparative change based on the transition from a glassy state to a rubbery state was read, and this temperature was taken as the glass transition temperature (Tg). The endothermic peak temperature based on the crystal melting was defined as the melting point (Tm), and the melting energy (ΔHu) was determined from the peak area. The correction was performed using the melting energy of indium.

(2) Average particle size of particles The polyester portion is removed from the sample by a plasma low-temperature incineration method (for example, RP-503 manufactured by Daiwa Chemical Co., Ltd.) to expose the particles. The processing conditions are selected such that the polyester is ashed but the particles are not damaged. This is observed with a scanning electron microscope (SEM), and the image of the particles is analyzed with an image analyzer (for example, QTM90 manufactured by Cambridge Instruments).
0), and the number average diameter D obtained by the following formula for the number of observed particles of 1,000 or more is defined as the average particle diameter.

 D = ΣDi / N Here, Di is the equivalent circle diameter of the particle, and N is the number.

(3) Content of Particles The polyester is dissolved, and the sample is melted using a solvent that does not dissolve the particles (for example, O-chlorophenol or the like), and the particles are centrifuged from the solution. The weight ratio (% by weight) is defined as the particle content.

(4) Thickness of [C] layer The ratio of the number of sulfur atoms / carbon atoms and / or the number of oxygen atoms / carbon atoms is measured from the surface by AES (Auger electron spectroscopy) while etching in the thickness direction. The inflection point was taken as the boundary between the [C] layer and the [B] layer, and the thickness was determined from the etching rate and the time required to reach the inflection point.
The measurement conditions are as follows.

Apparatus: JEOL JAMP-10S Etching conditions: Ar ion etching (acceleration voltage 3 kV) Etching rate: 160 minutes (5) [B] layer thickness The thickness (T1) of the sample is measured with an electronic micrometer. Next, the layer [B] of the measurement section is removed using a solvent (for example, n-methylpyrrolidone, etc.) that dissolves the layer [B] and the layer [C] but does not dissolve the layer [A]. Measure the thickness (T2).

From this result, the thickness of the [B] layer + [C] layer = T1−T2.

In each case, measurement was made at 20 points at different locations, and the average of 16 points obtained by omitting 2 points from the largest value and 2 points from the smallest value, the thickness of the [B] layer + [C] layer The value obtained by subtracting the thickness of the [C] layer obtained by the above method was defined as the thickness of the [B] layer.

(6) Intrinsic viscosity (IV) Measured at 25 ° C. using o-chlorophenol as a solvent. The unit is dl / g.

(7) Thermal adhesion The films are stuck together at 140 ° C, and the adhesion is measured by Tensilon after 12 hours. The peeling speed is 200 mm / min and the sample width is 15 mm.

(8) Adhesion strength of vapor deposition Aluminum metal is sampled on a sample of 500 mm width and 3000 mm length using an electron beam heating type vapor deposition machine, and the vapor deposition thickness is 500 mm.
And rolled it up. Next, the state when the deposited film was unwound was examined, and the presence or absence of blocking was examined.

(9) Slipperiness The following rank was evaluated when a film having a film width of 500 mm and a length of 3000 m was wound on a paper tube having an outer diameter of 3 inches. Incidentally, it is necessary to be ranked A for practical use.

 Rank A: can be rolled up without any problem without wrinkles.

Rank B: Wrinkles and the like are generated at the beginning of winding, but disappear during the winding process, and can be rolled up in appearance.

Rank C: Wrinkles and the like occur all the time and cannot be wound up neatly.

[Examples] The present invention will be specifically described using examples.

A resin prepared by adding 0.1% by weight of silica particles having an average particle diameter of 2 μm as inorganic particles to polyethylene terephthalate (IV = 0.66 dl / g, melting point = 260 ° C.) as a resin for the polyester [A] layer was prepared. Further, Polymer A and Polymer B shown in Table 1 were prepared as a resin for the polyester [B] layer, and Polymer C shown in Table 1 was prepared as a resin for the polyester [C] layer.

Example 1 Polymer A as a resin of the polyester [A] layer and a polymer A as a resin of the polyester [B] layer were respectively melt-extruded by different extruders, and were laminated at the die manifold section, and [A] / [B]
Was extruded. Next, after cooling and solidifying the molten sheet on a casting drum, the sheet was heated to 85 ° C. and roll-stretched 3.5 times in the longitudinal direction. After subjecting the surface of the [B] layer of the uniaxially stretched film thus obtained to a corona discharge treatment, an aqueous dispersion of the polymer C and spherical silica particles (Spherica 1000, average particle diameter 1 μm) were added at 10 wt. %, And applied so as to have a final lamination thickness of 0.1 μm.

Then, the coating film was guided to a stenter, stretched 3.8 times in the width direction, and heat-treated at the melting point of polymer B + 5 ° C. and wound.

The film thus obtained had a good thermal adhesive strength of 500 g / 15 mm and a good sliding property of rank A.

Example 2 In Example 1, a film having the structure shown in Table 2 was obtained as the polyester [C] layer, using Polymer B as the resin of the polyester [B] layer. As shown in Table 2, the properties of the film thus obtained were good in both thermal adhesive force and slipperiness.

Example 3 In Example 1, polymer A was used as the “B” layer so that the layer thickness was 3 μm, and a film was formed in the same manner except that the configuration of the “C” layer was as shown in Table 2. The film characteristics thus obtained were excellent as shown in Table 2.

Comparative Examples 1 and 2 In Example 1, 0.3% by weight of silica particles having an average particle diameter of 7 μm (Comparative Example 1) and 6% by weight (Comparative Example 2) were added to polyester [B] as inorganic particles. C] A film was formed without providing a layer. As a result, as shown in Table 2, it is found that at least one of the thermal adhesive force and the slip property is inferior, and it is difficult to achieve both the thermal adhesive property and the slip property.

Example 4 / Comparative Example 3 On the polyester [A] side of the film obtained in Example 1 and the film obtained in Comparative Example 1, the film thickness was reduced under vacuum.
Aluminum was vapor-deposited so as to have a thickness of 500 ° and wound (Example 4 and Comparative Example 3 respectively). Next, the appearance of unwinding the vapor-deposited film was examined. In Comparative Example 3, partial blocking occurred and aluminum escaped. In Example 4, no blocking occurred.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B32B 1/00-35/00

Claims (3)

(57) [Claims] 1. A layer [A] composed of a thermoplastic polyester A, a layer [B] composed of a polyester B having a melting point lower than that of the polyester A by 10 ° C. or more, and water dispersibility and / or water containing inert particles. A laminated polyester comprising: [C] a layer made of a soluble polyester C, and at least [A] / [B] / [C] laminated in this order, and [A] / [B] laminated at the time of melt extrusion. Film manufacturing method. 2. A water-dispersible and / or water-soluble polyester C containing a sulfonate group and / or a polyoxyalkylene glycol bonded to an ester-forming aromatic ring as a polymer segment thereof, and a polyester contained in the layer. The average particle size of the active particles is 0.01 to 5 μm, and the amount added is 0.1 to 50.
The method for producing a laminated polyester film according to claim 1, wherein the content is% by weight. 3. The [D] layer comprising a metal and / or metal oxide vapor deposited layer is formed as [D] / [A] / [B] / [C] or [D] / [C] / [A] / [B]. ] / [C]. The method for producing a laminated polyester film according to (1) or (2), wherein the laminated polyester film is laminated.