JP2005254525A - Heat shrinkable flocked film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an application technique of a heat shrinkable flocked film and the performance of an applied article by applying a heat shrinkable polyester film, particularly a heat shrinkable polyester film improved for a packaging material and a label to the heat shrinkable flocked film. <P>SOLUTION: The heat shrinkable flocked film preferably has the maximum heat shrinkage rate of at least 10%, and when a polyester substrate is used, contains neopentyl glycol and/or cyclohexane dimethanol as glycol components constituting a polyester. The shrinkage ratio in the rectangular direction to the main contraction direction has the minimum value in a temperature range of 80±25°C, the intersection shrinkage ratio is at least 2%. and the film can be bonded by a solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a heat-shrinkable flocked film. In particular, there is little unevenness of shrinkage, giving shrinkage results with excellent unidirectional shrinkage when necessary, and adhesive processing with solvents, making it possible to produce heat shrinkable flocked films with a wide range of applications, designability, tactile properties Toys, daily necessities such as stationery, building materials that require moisture control and design, indoor equipment such as wallpaper, mechanical parts such as rollers, ducts and fins, optical equipment that requires anti-reflection, labels that require design, It can be used for etc.
Here, the flocking process is a process for raising a surface of an object and is also called a pile process. By this processing, the treated surface has various aspects such as suede, velvet, carpet and fur.

  Since heat-shrinkable film has a function of shrinkability, it does not use fixing means such as adhesives and fasteners for the object to be applied, and it is laminated and integrated with the object by the shrinkage force and shapeability generated from the film. I can do it. Therefore, it has not only mechanical protection of the object by lamination and coating, but also functions such as binding and sealing. Furthermore, when the shrink film itself has a special function, the special function can be added to the target object by stacking. This property is effectively used in the packaging field where the main purposes are content protection (storage, distribution), display and design. For example, various types of containers such as bottles (including glass and plastic bottles) and cans, and long objects (pipes, rods, wood, various rods, etc.) or sheet-like bodies for covering, binding, exterior Or used for sealing. Specifically, it is used for applications that cover part or all of the cap part, shoulder part, and body part of the bottle for the purpose of improving the commercial value by displaying, protecting, binding, and functionalizing. Furthermore, it is also used for applications such as stacking and packaging a plurality of boxes, bottles, plates, sticks, notebooks, etc., and packaging (skin package) with a film in close contact with an object to be packaged.

As the material for the film, polyvinyl chloride, atactic polystyrene, polyester, polyamide, aliphatic polyolefin, derivatives thereof, hydrochloric acid rubber, and the like are used. Usually, these films are formed into a tube shape and, for example, covered with a bottle or pipes are collected, and then packaged or bound by heat shrinking. As a result of using materials with various properties in this way, there is a common or unique advantage for each material. If you list,
All of the above conventional films have poor heat resistance and cannot withstand high temperature boil processing and retort processing. Therefore, when applied to foods, sanitary goods, and pharmaceutical applications, there is a disadvantage that high temperature sterilization processing cannot be performed. . For example, when a retort process is performed, the conventional film is easily damaged during the process.

  When referring to the polyvinyl chloride film, this film has very good heat shrinkage properties, but it has poor adhesion to ink during printing, and it is easy to form a gel-like additive that is characteristic of the resin. , Pinholes are likely to occur on the printing surface of the film. Furthermore, there is a problem of environmental pollution when discarded and incinerated.

  The polyester film is excellent in heat resistance, dimensional stability, solvent resistance, and the like. However, in order to achieve desirable shrinkage characteristics, adhesion, etc., precise manufacturing condition control technology is required. Accordingly, in general, a resin is modified by using a copolymerization technique or a blend technique, and a stretching method corresponding to the resin to be used is developed and dealt with.

  Polystyrene film has a low density and is advantageous for separation in the recycling process, but has poor heat resistance. In addition, since it shrinks with time after production, a change in printing pitch due to shrinkage occurs, and high-precision printing cannot be performed. Furthermore, it was partly dissolved or swollen in the solvent contained in the printing ink, and good printing was difficult.

  As described above, although there is a difference depending on the material to be used, the heat-shrinkable film is also used in fields where other materials have been conventionally used because of the usefulness of the heat-shrinkable film.

  The present invention provides a heat-shrinkable flocked film, the purpose of which is heat resistant, excellent in shape stability, particularly less shrinkage unevenness, and unidirectionally shrinkable as required. It is intended to provide a heat shrinkable flocked film with a wide range of applications by giving excellent shrinkage results and being able to process with a solvent, thereby providing design, tactile properties, moisture absorption, moisture retention, and heat retention that flocked products have. Functions such as cold insulation, heat insulation, anti-condensation, anti-reflection, impact mitigation, slipping, friction, anti-static, etc. are to be imparted to the article by a post-processing step by thermal shrinkage, not by a flocking step.

  The technique in the present invention requires a heat-shrinkable flocked film using a heat-shrinkable base film and having a maximum heat shrinkage rate of 10% or more in one direction. When the maximum heat shrinkage rate is less than 10% in one direction, the weekly shrinkage adhesion to the target article deteriorates, causing wrinkles and slack.

  Use of a heat-shrinkable polyester film having a maximum heat shrinkage rate of 20% or more in one direction as a heat-shrinkable substrate film is advantageous in terms of heat resistance, shrinkage finish, recycling, and the like. The shrinkage rate should be about 20% or more in consideration of loss due to pile processing.

  When a heat-shrinkable polyester film is used as a heat-shrinkable substrate, it is necessary to obtain neopentyl glycol and / or cyclohexanedimethanol as a glycol component constituting the polyester in order to obtain suitable shrinkage properties and adhesiveness.

  In the heat-shrinkable polyester film, it is desirable that the shrinkage rate in the direction perpendicular to the main shrinkage direction has a minimum value in the temperature range of 80 ° C. ± 25 ° C. as necessary. This property provides complete unidirectional shrinkage and ensures design and construction, especially when applied to long items.

  In the heat-shrinkable polyester film, the intersection shrinkage is 2% or more. Due to this characteristic, the shrinkage spots are eliminated naturally, and the pile density can be made constant for the roll-shaped article.

  Since the heat-shrinkable polyester film is capable of solvent bonding, the strength of pile processing with a solvent-based adhesive is increased, and tube processing is facilitated.

  By using the heat-shrinkable flocked film of the present invention, the flocking process can be omitted in the manufacture of articles that require flocking, and a simpler heat-shrinking process can be achieved. Further, a flocking process can be performed as a post-processing on an article that has conventionally been difficult to flock. As a result, various characteristics of the flock processing are imparted to the completed article, and it can be easily updated again even when the function is deteriorated.

The present invention will be described more specifically.
In the present invention, any material may be used as the heat-shrinkable substrate as long as it has shrinkability. Examples thereof include polyethylene, polypropylene, polystyrene, polyamide, polyvinyl chloride, and polyester.

  Polyester resin used when a polyester film is used as a heat-shrinkable substrate, as a dicarboxylic acid component, one or more of aromatic dicarboxylic acids, their ester-forming derivatives, and aliphatic dicarboxylic acids. Known (copolymerized) polyesters polycondensed with the components can be used. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, and 5-sodium sulfoisophthalic acid. Examples of these ester derivatives include derivatives such as dialkyl esters and diaryl esters. Examples of the aliphatic dicarboxylic acid include dimer acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, oxalic acid, and succinic acid. Further, an oxycarboxylic acid such as p-oxybenzoic acid, and a polyvalent carboxylic acid such as trimellitic anhydride and pyromellitic anhydride may be used in combination as necessary.

Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, dimer diol, propylene glycol, triethylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 3- Alkylene glycols such as methyl 1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol, Examples include alkylene oxide adducts of bisphenol compounds or derivatives thereof, trimethylolpropane, glycerin, pentaerythritol, polyoxytetramethylene glycol, polyethylene glycol and the like. Moreover, although it is not a polyhydric alcohol, (epsilon) -caprolactone can also be used.
In the present invention, the polyhydric alcohol component is particularly preferably selected from neopentyl glycol and 1,4-cyclohexanedimethanol in terms of heat shrinkability.

The polyester raw material which comprises a heat-shrinkable polyester-type film base material may be individual, and may mix and use 2 or more types. When used alone, homopolyesters other than polyethylene terephthalate such as polybutylene terephthalate, polycyclohexylene dimethyl terephthalate, and polyethylene naphthalate are preferable. This is because polyethylene terephthalate alone does not exhibit heat shrinkability.
From the viewpoint of heat shrinkage characteristics, it is preferable to use a blend of two or more polyesters having different Tg. It is preferable to use a mixture of polyethylene terephthalate and copolymerized polyester (which may be two or more types), but it may be a combination of copolymerized polyesters. Moreover, polybutylene terephthalate, polycyclohexylene dimethyl terephthalate, and polyethylene naphthalate can be combined, or these can be used in combination with other copolyesters. Three types of blends of polyethylene terephthalate, polybutylene terephthalate, a mixed diol component of ethylene glycol and neopentyl glycol, and a copolyester composed of terephthalic acid are most preferable in terms of heat shrinkage characteristics. When two or more kinds of polyesters are used in combination, as described above, it is preferable from the viewpoint of production efficiency that the respective polymer chips are blended in a hopper.

  Polyesters can be produced by melt polymerization in the usual way, but the so-called direct polymerization method in which oligomers obtained by direct reaction of dicarboxylic acids and glycols are polycondensed, dimethyl ester of dicarboxylic acid and glycol are transesterified. Examples include a so-called transesterification method in which polycondensation is performed after the reaction, and any production method can be applied. Moreover, the polyester obtained by another polymerization method may be sufficient. The polymerization degree of polyester is preferably 0.3 to 1.3 dl / g in terms of intrinsic viscosity.

  In addition to polymerization catalysts such as antimony oxide, germanium oxide, and titanium compounds, polyester such as magnesium acetate, magnesium chloride and other Mg salts, calcium acetate, calcium chloride, etc. Ca salt, manganese acetate, manganese chloride and other Mn salts, zinc chloride, zinc acetate and other Zn salts, cobalt chloride, cobalt acetate and other Co salts, respectively, with respect to the polyester as 300 ppm or less, phosphoric acid or Phosphoric acid ester derivatives such as phosphoric acid trimethyl ester and phosphoric acid triethyl ester may be added in an amount of 200 ppm or less in terms of phosphorus (P).

If the total amount of metal ions other than the above polymerization catalyst is 300 ppm with respect to the polyester and the amount of P exceeds 200 ppm, not only the coloration of the polymer becomes remarkable, but also the heat resistance and hydrolysis resistance of the polymer are remarkably lowered. .
At this time, in terms of heat resistance, hydrolysis resistance, etc., the molar atomic ratio (P / M) of the total P amount (P) and the total metal ion amount (M) is 0.4 to 1.0. It is preferable. When the molar atomic ratio (P / M) is less than 0.4 or exceeds 1.0, it is not preferable because the film may be colored or coarse particles may be mixed in the film.
The timing of adding the above metal ions, phosphoric acid and derivatives thereof is not particularly limited. In general, metal ions are added at the time of raw material charging, that is, before transesterification or esterification, and phosphoric acids are added before polycondensation reaction. It is preferable to do this. Moreover, you may add fine particles, such as a silica, titanium dioxide, a kaolin, a calcium carbonate, as needed.

In order to improve electrostatic adhesion, slipperiness, stretchability, processability, impact resistance, etc. for the polyester polymer used in the present invention, such as roughening, opacification, hollowing, weight reduction, etc. Depending on the reason, other resins, foaming agents, plasticizers, compatibility adjusting agents, inorganic particles, organic particles, colorants, antioxidants, ultraviolet absorbers, antistatic agents and the like can be appropriately used. .
The polyester resin includes one or more kinds of polyester copolymerization monomer species, copolymerization ratio, blending ratio, and stretching conditions, and the characteristics and ultrasonic adhesiveness, thermal adhesiveness and solvent adhesion shown in the claims. Can have sex. In particular, as a solvent used for solvent adhesion, one having an SP value of 8.0 to 13.8, preferably tetrahydrofuran, dioxolane or the like can be used.

  In order to improve electrostatic adhesion, slipperiness, stretchability, processability, impact resistance, etc. for the polyester polymer used in the present invention, such as roughening, opacification, hollowing, weight reduction, etc. Depending on the reason, other resins, foaming agents, plasticizers, compatibility adjusting agents, inorganic particles, organic particles, colorants, antioxidants, antistatic agents and the like can be appropriately used.

  The polyester-based composition is formed into a film by a known method (for example, an extrusion method or a calendar method). The shape of the film is, for example, a flat shape or a tube shape, and is not particularly limited. A normal method is adopted as the stretching method. Examples thereof include a roll stretching method, a long gap stretching method, a tenter stretching method, and a tubular stretching method. In any of these methods, stretching is performed by sequential biaxial stretching, simultaneous biaxial stretching, uniaxial stretching, and combinations thereof. In the biaxial stretching, stretching in the vertical and horizontal directions may be performed at the same time, but sequential biaxial stretching in which one of the two is performed first is effective, and either of the longitudinal and horizontal orders may be first. The draw ratio is arbitrarily set in the range of 1.0 to 6.0 times, and the magnification in one predetermined direction and the magnification in the direction orthogonal to the direction may be the same or different. In the stretching step, preheating is preferably performed at a temperature not lower than the glass transition temperature of the polymer constituting the film, for example, not higher than Tg + 100 ° C. In the heat setting after stretching, for example, it is recommended to pass through a heating zone of 30 ° C. to 150 ° C. for about 1 second to 30 seconds after stretching. Further, after the film is stretched and before or after heat setting, the relaxation treatment may be performed at a predetermined degree. Further, after the stretching, a step of cooling while applying a stress to the film while keeping the stretched or tensioned state, or a cooling step after releasing the tensioned state following the treatment may be added. The thickness of the obtained film is preferably in the range of 6 to 250 μm.

In particular, when the heat-shrinkable flocked polyester film of the present invention is prepared, the base film is TD after stretching 1.0 to 2.0 times in the MD direction with reference to the description of European Patent EP210646B. Stretching in the direction, and additional additional stretching in the TD direction, the shrinkage rate in the direction perpendicular to the main shrinkage direction has a minimum value in the temperature range of 80 ° C. ± 25 ° C., and in one direction in the TD direction It is possible to obtain the property of shrinking uniformly only on the surface. Therefore, for example, when a flocked film is applied to the surface of the roll, a tube processed with the same width as the roll can be applied, and there is no need to finely adjust the position in the width direction. Further, referring to the description in EP0271928B, preheating is performed at a temperature of Tg + 80 ° C. or lower in TD stretching, and the remaining 10% temperature is lowered from the temperature up to the first 90% during TD stretching. Slightly additional stretching increases the intersection shrinkage, and the value can be 2% or more, preferably 5% or more. As a result, the property of self-repairing the spots of heat shrinkage is obtained. Therefore, for example, when a flocked film is applied to the surface of the roll, the density of the flock is constant at any position of the roll.
When the film is applied in a tube form, the flocking can be used on the outside, inside, or both sides of the tube.
The flock and pile used in the present invention are not particularly limited. Examples thereof include cotton, nylon, rayon, polypropylene, and polyester. These may be subjected to conductive treatment, antistatic treatment, dyeing, water repellent treatment, moisturizing treatment, etc. according to the function to be added by the pile processing and the processing method. A loop shape in which suitability is expected, a powder shape in consideration of friction, and the like can be applied.

As the adhesive used for the flocking process, either an emulsion type or a solvent type may be used. In particular, the film substrate used in the present invention is also suitable for solvent-based adhesives.
Although it does not specifically limit regarding a flock processing method, When processing a film base material, an electrostatic flocking method is common. This step may be performed off-line after production of the film substrate, or may be performed before the substrate is stretched or after uniaxial stretching. In the flocking process, the management of the temperature of the film substrate is important. Although it depends on the type of the shrink film substrate, the upper limit of the temperature in the adhesion drying process is determined so that the shrinkage force is not relaxed. For example, in the case of a polyester-based material, the shrinkage direction is in a tension state, and it is preferably 100 ° C. or lower, desirably 80 ° C. or lower. If it is 60 ° or less, it may be possible even in an unstrained state.

  The heat-shrinkable flocked film thus obtained solves the problems of conventional flocking. It has the inherent heat resistance of polyester, does not deform with time due to natural shrinkage, and can achieve uniform flock density, improving the mechanical reliability and design of the applied article, and with excellent one-way shrinkage when necessary. Therefore, application becomes easy, and adhesion processing with a solvent can be performed, whereby adhesion of floc, adhesion processing to an object, and efficiency thereof can be improved.

The present invention will be specifically described below with reference to experimental examples, but the present invention is not limited to these experimental examples.
The evaluation method of a film is shown below.

1) Maximum heat shrinkage rate The direction of shrinking the film or its substrate is taken as the long side, and the film is cut out to have a width of 15 mm. Marks are marked at intervals of 200 mm in the long side direction. The sample is heated by applying hot air at 100 ° C. to 150 ° C. for 1 minute, and the amount of change in the distance between the marked lines is measured. The percentage of the change amount with respect to the original length is defined as a heat shrinkage rate (%).

2) Shrinkage ratio in the direction perpendicular to the main shrinkage direction According to EP210646B, the film is cut out so that the direction perpendicular to the direction in which the film shrinks is the long side and the width is 15 mm. Marks are marked at intervals of 200 mm in the long side direction. The sample for each temperature from 50 ° C. to 150 ° C. at a pitch of 5 ° C. is heated by applying hot air at each temperature for 1 minute, and the amount of change in the distance between the marked lines is measured. The percentage of the change amount with respect to the original length is defined as a heat shrinkage rate (%). From this, a graph of shrinkage temperature to shrinkage rate is created, and it is determined whether or not there is a minimum value in the temperature range of 80 ° C. ± 25 ° C.

3) Interstitial shrinkage rate Tensilon was used to obtain heat shrinkage stress in accordance with EP 0271928B (Japanese Patent Laid-Open No. 64-4325), and a sample piece having a width of 20 mm and a length of 150 mm was collected on the film substrate. A sample piece was attached to an upper and lower chuck set to an arbitrary dimension (L1) smaller than 100 mm and larger than 50 mm, marked with a mark of 100 mm, and treated in hot air at 100 ° C. to shrink the film.
The residual shrinkage stress at this time was obtained and the stress was obtained by the following equation.
Shrinkage force / cross-sectional area = residual shrinkage stress or shrinkage at that time was calculated by the following equation.
Shrinkage rate = (100−L1) / 100 × 100 (%)

On the other hand, the tensile stress is 50% in the measurement of the residual shrinkage stress, and the tensile force required to return the chuck distance L2 to an arbitrary chuck distance L2 that is greater than 50 mm and less than 100 mm is obtained by the following equation. Asked.
Tensile force / cross-sectional area = tensile stress Re-extension rate = (L2-50) / 50 × 100 (%)
The shrinkage rate corresponding to the intersection obtained from the graph showing the relationship between the residual shrinkage stress and the shrinkage rate and the tensile stress and the re-elongation rate is defined as the intersection shrinkage rate.

(Example 1)
PET: 20 wt%, neopentyl glycol 30 mol% copolymerized PET: 70 wt%, adipic acid 30 mol% copolymerized PET: 10 wt% were melt extruded at 280 ° C. to obtain an unstretched sheet having a thickness of 180 μm. The unstretched sheet is stretched 1.3 times in the MD direction at 80 ° C. using a roll stretching machine, and then preheated at 130 ° C. using a tenter-type stretching machine. The part was stretched at 70 ° C. and heat fixed at the same temperature for 2 seconds. Furthermore, 2% stretching was performed at 65 ° C. in the TD direction, and the total stretching ratio in the TD direction was 4.5 times. This film substrate has a minimum value of shrinkage in the MD direction at 80 ± 25 ° C., and the shrinkage at the intersection is 2% or more. An acrylic emulsion adhesive is applied to the shrinkable film substrate, and electrostatic flocking is performed using a straight nylon flock having a diameter of 44 μm and a length of 3 mm.

Claims (6)

  A heat-shrinkable flocked film obtained by flocking at least one surface of a heat-shrinkable base film having a maximum heat shrinkage rate of 10% or more in one direction.   The heat-shrinkable polyester film according to claim 1, wherein the maximum heat-shrink rate is 20% or more in one direction.   It is a heat-shrinkable polyester film of Claim 2, Comprising: Neopentyl glycol and / or cyclohexane dimethanol are included as a glycol component which comprises polyester, The heat-shrinkable flock processed film characterized by the above-mentioned.   The heat-shrinkable polyester film according to claim 2, wherein the shrinkage in the direction perpendicular to the main shrinkage direction has a minimum value in a temperature range of 80 ° C ± 25 ° C.   The heat-shrinkable polyester film according to claim 2, wherein the shrinkage at the intersection is 2% or more.   The heat-shrinkable polyester film according to claim 2, wherein the film can be bonded to a solvent.