JPH07119097B2 - Polyester laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transparent polyester laminate used for metal overlays, base films for video printers, and the like.

[Prior Art] Conventionally, as a film used for a base film for a video printer, a biaxially oriented polypropylene-based opaque film or a biaxially oriented polyester-based transparent film has been used.

A biaxially oriented polypropylene-based film is made by blending polypropylene resin with a large amount of inorganic particles and stretching it to create voids, improving cushioning properties during printing and improving printability, running properties, and sheet-fed properties. ing. A biaxially oriented polyester-based film is a biaxially oriented polyethylene terephthalate film (hereinafter PET-B).
(O film) or a PET-BO film with a thin easy-dye coating layer formed on the surface.

[Problems to be Solved by the Invention] However, conventional base films have the following drawbacks.

(1) The biaxially oriented polypropylene base film is deformed by curling due to heating during printing.

(2) The biaxially stretched polyester-based film has poor printability, running property, and sheet-fed property at the time of printing, so that a printed image or an image is unclear, a so-called dropout occurs, or a color shift occurs. Therefore, a good polyester film for thermal transfer (a film excellent in heat transfer acceptance of dye or ink and running property) has been demanded.

(3) Since the blocking of the film layer is large at the time of thermal transfer, not only blocking marks remain on the printed matter as trace marks, but also the sheet-fed property is poor and printing cannot be performed one by one.

The object of the present invention is to eliminate the above-mentioned drawbacks, substantially no traces due to blocking during handling of a base film, printability during printing (transferability of dyes and inks), transparency and deformation resistance. It is intended to provide a transparent polyester laminate and a laminate for a video printer which are excellent in sheet-fed property.

[Means for Solving Problems] The present invention provides a biaxially stretched polyethylene terephthalate film (A) having a thickness of 30 to 160 μm and a haze of 10% or less, and a thickness of 5 to 5.
In a laminate (C) obtained by laminating a 40μ copolyester film (B), the haze of the laminate (C) is 20%.
Hereinafter, the Vickers hardness ratio (B / A) of the film (B) and the film (A) is 0.08 to 0.9, the surface roughness of the film (B) is 0.008 to 0.2 μ, and the surface roughness of the film (A) is 0.
The present invention relates to a polyester laminate characterized by having a size of 008 to 0.1 µ.

The PET-BO film (A) used in the present invention means polyethylene terephthalate (hereinafter referred to as PET) by a conventional method.
It is an axially stretched film. Further, PET is preferably ethylene terephthalate units having 80 mol% or more, and more preferably 90 mol% or more. Of course, other types of dicarboxylic acid components (for example, naphthalenedicarboxylic acid, isophthalic acid, adipic acid, sebacic acid, etc.) or diol components (for example, cyclohexanedimethanol, diethylene glycol, polyethylene glycol, neopentyl glycol, etc.) can be used together within the above range. It may be polymerized. Further, various well-known additives (for example, inorganic particles, lubricants, antioxidants, antistatic agents, etc.) may be added to this PET within a range that does not impair the purpose.

The PET-BO film (A) has a thickness of 30 to 160 µ, preferably 40 to 125 µ. If it is less than 30μ, it is too thin to maintain the hardness as a support film, and if it is thicker than 160μ, it becomes too hard and lacks flexibility.

Haze of PET-BO film is 10% or less, preferably 5%
It is the following. If the haze exceeds 10%, when a printed product is projected using transmitted light such as an overhead projector (hereinafter referred to as OHP), the screen becomes dark and the print or image becomes unclear.

As the copolyester film for the film (B) layer,
As the dicarboxylic acid component, terephthalic acid, isophthalic acid, isophthalic acid-5-sulfate sodium salt, adipic acid, sebacic acid and the like, and as the diol component, ethylene glycol, 1,4-butanediol, diethylene glycol, polyethylene glycol, neopentyl glycol, It is a copolyester composed of cyclohexanedimethanol, an ethylene oxide adduct of bisphenol A, and the like.

The layer (B) has a thickness of 5 to 40 µ, preferably 11 to 35 µ, and more preferably 13 to 30 µ. If it is less than 5 μm, printing and sheet-fedness are unsuitable for printing, and if it exceeds 40 μm, film-forming properties and transparency become problems. In addition, various known additives (for example, inorganic particles, lubricants, antioxidants, antistatic agents, etc.) may be added to the B layer within a range that does not impair the purpose.

The melting point or softening point of the B layer is preferably 70 to 240 ° C, more preferably 75 to 220 ° C. If the melting point or softening point is 70 ° C. or less, not only the printed image or image is distorted by heating during printing, but also defects such as flocking are likely to occur. When the temperature exceeds 240 ° C, the layer (B) becomes too hard, which may result in improper printing and sheet-fed properties.

The haze in the laminate (C) in which the (A) layer and the (B) layer are laminated is 20% or less, preferably 15% or less, and more preferably 10% or less. When the haze of the layered product (C) exceeds 20%, the screen becomes dark when a printed product is projected by using transmitted light such as OHP, so that printing or an image becomes unclear.

The Vickers hardness ratio (B / A) of the layer (A) and the layer (B) in the laminate (C) is 0.08 to 0.9, preferably 0.1 to 0.85. If the B / A is less than 0.08, blocking of the laminate becomes a problem, or the hardness as a support becomes insufficient. Also
When B / A is larger than 0.9, the layer (B) of the laminate (C) becomes hard and does not serve as a cushion layer, resulting in poor print running suitability during printing. The surface roughness (Ra) of the layer (B) in the laminate (C) is 0.008 to 0.2 µ, preferably 0.01 to 0.15 µ. When the Ra of the layer (B) is 0.008 or less, blocking becomes a problem when handling the laminate, which may cause a trace residue. If it exceeds 0.2 μm, light scattering occurs, so that clear printing and images cannot be obtained.

The surface roughness (Ra) of the layer (A) which is the other surface of the laminate (C) is
It is 0.008 to 0.1, preferably 0.01 to 0.08. Ra is 0.008
If it is less than the above range, blocking becomes a problem when handling the laminate, which may cause a trace residue. On the other hand, if it exceeds 0.1 μ, it may cause printing, image distortion, and unclearness due to light scattering. The transfer receiving layer coated on the copolyester film (B) layer is a layer which functions to receive the ink or dye transferred from the thermal transfer sheet, and is generally a polyester resin, a polyvinyl chloride resin, A synthetic resin such as a polyamide resin or a polyurethane resin, and a mixture or copolymer thereof are used. To improve releasability and slipperiness, waxes, silicones, silica, calcium carbonate and the like can be added to these synthetic resins within a range that does not impair the purpose.

Next, a method for manufacturing the laminated body of the present invention will be described, but the present invention is not limited to this.

(1) Method for producing laminated body by melt extrusion laminating A resin to be the layer (B) is supplied to an extruder and melt-extruded and laminated on PET-PO prepared in advance to a target thickness. If necessary, the PET-BO may be preheated with an oven or a radiation heater in order to strengthen the adhesive force between the PET-BO and the (B) layer. A primer may be applied.

(2) You may form a laminated body by a composite film forming method.

A method in which PET and the (B) layer resin are co-extruded and then biaxially stretched, or a method in which the B layer is extrusion-laminated on a uniaxially stretched PET film and then laterally stretched. The layer for receiving the thermally transferred ink layer may be formed by a known method such as bar coating, reverse coating, or gravure coating (B).
It can be coded on the layer surface.

[Effects of the Invention] The present invention has the following excellent effects because the specific PET-BO and the specific copolyester film are laminated to specify the hardness ratio and the surface roughness.

(1) It is excellent in printability at the time of printing (transfer acceptance of ink by thermal transfer).

(2) A laminate that is transparent and substantially free of blocking marks, and the projected image after printing is clear.

(3) Heat resistance is excellent, and the laminate is not substantially curled and deformed after printing.

Since the laminate of the present invention is excellent in transparency, it can be used as a metal overlay film by laminating the layer (B) with a metal as an adhesive layer, or as a laminate for a disc mat.

[Evaluation method] (1) Film thickness Measured according to JIS Z1720.

(2) Film haze Measured according to ASTM-D-1003-52.

(3) Vickers hardness Measured according to JIS-B-7734.

(4) Film surface roughness (Ra) Ra was measured under the condition of 0.25 mm cutoff according to JIS BO601.

(5) Suitability for printing (printing) during printing After the thermal transfer receiving layer was coated on the (B) side of the laminate (C) by 3 μ, Sharp Corporation Video Printer GZ-P1
Printing was performed at 1 W and the printing state was observed.

◯: Printed, good image x: Printed, unclear image, partly missing (6) Transparency during printing The laminate was left in an oven heated to 120 ° C for 25 minutes, and the change in transparency was observed. did.

◯: Change in haze of 5% or less X: Change in haze of 5% or more (7) Runability during printing Laminates were printed using Sharp Video Co. GZ-P11W, and laminated during printing. The body running property was observed.

◯: Things that run smoothly X: Things that do not run smoothly and the stack does not run because it bends or folds (8) Deformation due to curl after printing The stack after printing is flat with the print side facing up. It was placed on top and the deformation due to curl was observed.

◯: Substantially no curling deformation.

X: Deformed due to curl.

(9) Blocking resistance The laminate (C) was wound into a roll and placed in an oven at 35 ° C.
After standing for 24 hours, the film was rewound at a speed of about 10 m / min.

○: Items that can be smoothly rewound.

X: Large blocking, difficult unwinding, and traces.

[Examples] The present invention will be described below based on Examples.

Examples 1 to 6 and Comparative Examples 1 to 8 (1) Extrusion Lamination on PET-BO As a PET-BO film for the layer (A), T60 type # 25, # 38, “Lumirror” manufactured by Toray Industries, Inc. # 75, # 120, T30 type # 75, S10 type # 38, # 75 and "Torayfan BO" 2300 type # 50 manufactured by Toray Industries, Inc.

As the resin for the layer (B), copolymerized polyesters I, II, III, I
Select V, V, VI.

Copolyester resin I: terephthalic acid / isophthalic acid (molar ratio = 95/5). Copolymerized polyester resin consisting of ethylene glycol / ethylene oxide adduct of bisphenol A / cyclohexanedimethanol (molar ratio = 65/25/10). [Melting point: 160 ° C.] Copolyester resin II: terephthalic acid / isophthalic acid (molar ratio = 78/22). Copolyester resin consisting of ethylene glycol / cyclohexanedimethanol (molar ratio = 70/30) [softening point: 82 ° C.] Copolyester resin III: terephthalic acid / isophthalic acid (molar ratio = 80/20). Ethylene glycol (molar ratio = 1
Copolymerized polyester resin consisting of 00) [melting point: 210 ° C] Copolyester resin IV: terephthalic acid / adipic acid (molar ratio = 56/44). Ethylene glycol / 1,4-butanediol (molar ratio = 32/68). Copolymerized polyester resin consisting of 2.7% by weight of polytetramethylene glycol [melting point:
109 ° C] Copolyester resin V: terephthalic acid / isophthalic acid (molar ratio = 65/35) .1,4-butanediol (molar ratio = 10
0) Copolymerized polyester resin [melting point: 165 ° C.] Copolyester resin VI: terephthalic acid / isophthalic acid (molar ratio = 92/8). Ethylene glycol (molar ratio = 10
Copolymerized polyester resin consisting of 0) [melting point: 240 ° C.] These resins are formed on the PET-BO film which is the layer (A),
40mmφ extruder with T-die (L / D = 22, compression ratio = 40,
(A) / (B) laminate (C) was obtained by melt extrusion through the combination of the PET-BO film shown in Table 1 and the thickness.

The unevenness of the surface of the PET-BO film of the (A) layer used in Example 6 and Comparative Example 5 and the unevenness of the surface of the (B) layer used in Example 5 and Comparative Example 8 were 80 to 140 ° C. Roughened PET-B using a heated press roll laminator
It was created by transferring the unevenness of the O film.
The PET-BO film serving as the surface of the layer (A) is a single layer and is a roughened film, and the layer (B) serving as the surface of the layer (B) is a laminate (C) and is then combined with the surface of the roughened film, After low-speed laminating, the roughened PET-BO was removed before use.

(2) Coating on Laminated Body The following composition was bar-coated on the B side of the laminated body (C) as an ink receiving layer in a thickness of 3 μ (solid content) to obtain a thermal transfer receiving film of Table 1.

Terephthalic acid / isophthalic acid (molar ratio = 55/45), ethylene glycol / neopentyl glycol (molar ratio 55/4
5) Polyester resin consisting of [molecular weight: 10000] 10 parts by weight, carnauba wax (Toa Kasei Co., Ltd.) 1.0 part by weight, toluene / methyl ethyl ketone = 1/1 89 parts by weight The laminates of Examples 1 to 6 were used. The product showed excellent transparency and supportability during printing and was excellent in printability of a dye or ink by thermal transfer. In addition, there was substantially no deformation due to curling after printing, the laminated film (C) had good slipperiness, and neither blocking nor traces was observed.

On the other hand, in the film using the PP-BO simple film of Comparative Example 1, the laminate was curled and deformed due to heating during printing.

Comparative Examples 2 and 7 had large Vickers hardness ratios of 1.0 and 0.92, and Comparative Example 4 had poor printability during printing because the thickness of the (B) layer was 3 μm which was too thin.
Comparative Example 5 having a Vickers hardness ratio of less than 0.08 is PE
Blocking against T-BO was large, and there was a problem in unrolling and leaving traces.

In Comparative Example 3, since PET-BO was as thin as 25 μ, it was too soft and had a problem in running property during printing.

Comparative Example 4 having a large (A) layer haze of 15%, Comparative Example 5 having a large surface roughness of the (A) layer of 0.14, Comparative Example 6 having a large haze value of 35 after being crystallized, The surface roughness of the (B) layer is
Comparative Example 8 having a large value of 0.22 had drawbacks such as printing after printing, the image was unclear, and the screen was dark when projected with transmitted light, and the printing and image were unclear. In Comparative Example 6, curled deformation due to crystallization of the (B) layer was also observed.

In Comparative Example 2 in which the surface roughness of the (A) layer and the (B) layer was as small as 0.003, 0.003, the blocking of the film itself was large and it was substantially unusable.

Claims (1)

[Claims] 1. A biaxially stretched polyethylene terephthalate film (A) having a thickness of 30 to 160 μm and a haze of 10% or less, a thickness of 5
A laminate (C) obtained by laminating a copolyester film (B) having a thickness of about 40 μm, the haze of the laminate (C) is 20.
% Or less, the Vickers hardness ratio (B / A) of the film (B) and the film (A) is 0.08 to 0.9, and the surface roughness of the film (B) is 0.008 to 0.2 μ, the surface roughness of the film (A). But
A polyester laminate characterized by having a thickness of 0.008 to 0.1 µ.