JP4366638B2 - Adhesive nonwoven fabric and method for producing the same - Google Patents

Description

  The present invention relates to a non-woven fabric that can be bonded to each other with a solvent or to a sheet-like material such as a non-woven fabric and a film, and a method for producing the non-woven fabric.

  As a material having adhesiveness by a solvent, there is a polyester shrinkable film as disclosed in Patent Document 1. However, although the film has excellent printing characteristics, it has a problem in mechanical properties such as tear resistance. On the other hand, since the surface of the nonwoven fabric is not smooth, the sharpness of printing is not good, and there is no information on the nonwoven fabric having adhesiveness with a solvent as far as the present inventors know.

Shrinkable films have been used as packaging materials and label materials for PET bottles and aluminum cans. However, these films have the function of providing clear printing from the viewpoint of product names and contents, but have little thermal insulation, and when the contents are hot, they burn when held by hand. There was a problem such as.
As a method for solving the above problem, an attempt has been made to attach a nonwoven fabric to a film. For example, Patent Document 2 discloses a heat insulating material in which a nonwoven fabric and a film are combined and then wound around a cylindrical container and attached with an adhesive. However, there is a problem that followability to a container having curved surfaces with different curvatures such as a neck portion of a bottle is inferior, and that sticking takes time. Known methods cannot achieve the object of the present invention.

JP-A-6-345878 JP-A-8-126663

  The present invention intends to provide a nonwoven fabric that can be bonded at a high speed of approximately 20 m / min or more with a solvent. Another object of the present invention is to provide a non-woven fabric that can be fixed to an object simply by covering the object and subjecting it to a heat shrinkage process on an object such as a bottle or cup having a shape other than a flat surface.

The present invention takes the following means in order to solve the above-mentioned problems. That is,
A first invention is a solvent-bondable nonwoven fabric characterized by comprising a nonwoven fabric having a fiber filling ratio of 0.05 to 0.5 made of a solvent-swelling fiber having a fiber diameter of 0.5 to 30 μm.

  A second invention is the solvent-bondable nonwoven fabric according to the first aspect, wherein the nonwoven fabric has a thickness of 0.05 to 1.0 mm and the bonded area of the nonwoven fabric is 5% or more.

  A third invention is the solvent-adhesive nonwoven fabric according to the first aspect, wherein the solvent-swelling fiber is made of a polyester resin or a polystyrene resin.

  According to a fourth aspect of the present invention, there is provided the solvent-bondable nonwoven fabric according to the third aspect, wherein the polyester resin is a polyester resin copolymerized using isophthalic acid as at least a part of an acid component.

  The fifth invention is the solvent-bondable nonwoven fabric according to the third or fourth aspect, wherein the polyester resin is a polyester resin copolymerized with neopentyl glycol as at least a part of an alcohol component. It is.

  Further, the sixth invention is the solvent-bondable nonwoven fabric according to the third aspect, wherein the polyester resin is a biodegradable polyester.

  The seventh invention is characterized in that the non-woven fabric has shrinkage anisotropy in which the difference in dry heat shrinkage at 100 ° C. between one direction and the direction perpendicular thereto is 5% or more. Is a non-woven fabric.

  In an eighth aspect of the invention, a solvent-swelling fiber having a fiber diameter of 0.5 to 30 μm is spun at a spinning speed of 100 to 5000 m / min by the spunbond method, and then the obtained nonwoven fabric is heated at a temperature of 40 to 180 degrees. A method for producing a solvent-bondable nonwoven fabric, characterized in that a crimped portion of a fiber is formed by an embossing roll or flat calendering with an area ratio of 5% or more.

  INDUSTRIAL APPLICABILITY According to the present invention, there is provided a nonwoven fabric that can be bonded to each other by a solvent or a sheet-like material such as a nonwoven fabric and a film, and a method for producing the nonwoven fabric. To. In addition, the nonwoven fabric of the present invention can be controlled in a shrinkable manner around the object so that the degree of shrinkage can be controlled and can be intimately combined. Furthermore, it is possible to make the nonwoven fabric excellent in moldability.

  The nonwoven fabric used in the present invention is a material having excellent processability and is not particularly limited as long as it is a material capable of controlling the solvent swellability of the constituent fibers, but is preferably a polymer material from the viewpoint of controlling shrinkage. . Examples of the polymer material applicable to the present invention include polyolefin, polyester, polyamide, polyimide, polyarylene sulfide and the like. In recent years when environmental issues are important, it is more preferable to use polyester that can be easily recycled.

  The nonwoven fabric of the present invention is considered to be often applied to packaging of containers such as PET bottles, but these containers are the same material that can be recycled at the same time because polyester is used as a raw material. Is particularly preferred. Polyester is a semi-crystalline material, and a non-woven fabric is particularly preferable because it can easily control shrinkage by controlling processing conditions. When a heat insulating material is shrunk in a container having a nonuniform container curvature, high shrinkage is required. In this case, it is also one of preferred embodiments to use a block copolymer polyester comprising a hard segment and a soft segment. The film made of the block copolymer polyester is non-porous and has moisture permeability, so that it is particularly effective when the anti-condensation function is important. In addition, since the material has elasticity, it can be easily attached to and detached from the container and has an effect of good adhesion at the time of attachment. Furthermore, it is particularly preferable that the material used including the heat insulating material and the container is made biodegradable, so that the container soiled with food such as instant noodles and drinks can be landfilled as it is.

  Examples of the nonwoven fabric material in the present invention include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyethylene naphthalate, polylactic acid, polylactone, and other polyesters, as well as acid components such as isophthalic acid, adipic acid, and sebacic acid. Examples thereof include copolymer polyesters obtained by copolymerizing alcohol components such as pentyl glycol, cyclohexane dimethanol, and diethylene glycol, and polyester block copolymers having polyalkylene glycols such as polytetramethylene glycol and polyethylene glycol as soft segments. The copolymerization component is preferably 2 to 50 mol%, more preferably 4 to 40 mol%, based on the acid component or alcohol component of the polyester. These polymers can be used by appropriately blending in order to obtain desired shrinkage characteristics and physical properties. For example, a copolyester in which ethylene terephthalate unit is the main component and neopentyl glycol is copolymerized as the third component can be blended with a homopolyester such as polyethylene terephthalate to control the shrinkage and physical properties of the nonwoven fabric to the desired range. can do. In this case, the blend ratio of the copolyester is preferably 25 to 80%, more preferably 30 to 60%.

  Polystyrene such as syndiotactic polystyrene can also be used because it has good processability and easily expands in the solvent.

The nonwoven fabric used in the present invention is preferably a nonwoven fabric having a fiber diameter of 0.5 to 30 μm and a basis weight of 5 to 200 g / m ² . If the fiber diameter is thinner than 0.5 μm, the nonwoven fabric is likely to fluff due to wear and the like, and the strength of the nonwoven fabric is reduced, which is not preferable. When the fiber diameter is thicker than 30 μm, the excellent adhesiveness aimed by the present invention is lowered, which is not preferable. In addition, a problem that the sharpness when printing is performed is likely to occur. Within the scope of the study by the present inventors, it was particularly preferred that the fiber diameter be between 3 and 17 μm. Laminating non-woven fabrics having different fiber diameters is also a preferred form. In addition, it is possible to laminate a non-woven fabric that is difficult to swell with a solvent depending on the purpose.
Moreover, when the fabric weight of a nonwoven fabric is smaller than 5 g / m < ² >, heat insulation and a nonwoven fabric intensity | strength will become low and it will become easy to generate | occur | produce the problem that lamination | stacking with a film etc. becomes difficult. When the weight per unit area exceeds 200 g / m ² , the weight of the container when used becomes heavy, and a problem of generating wrinkles when the laminated film contracts easily occurs. In order to increase the strength of the nonwoven fabric, the fibers may be partially bonded by embossing or calendering. As a form of the nonwoven fabric, a wet nonwoven fabric or a dry nonwoven fabric may be used, but a dry nonwoven fabric excellent in the deformability of the nonwoven fabric and easily increasing the heat insulation by increasing the thickness is more preferable. In particular, a long-fiber nonwoven fabric is more preferable because it has excellent strength and elongation properties and has a smooth surface and thus has good adhesion to a film or the like. Moreover, a dry nonwoven fabric is preferable also from the point that it is easy to change the shrinkage ratio in the longitudinal direction and the transverse direction if necessary. The solvent adhesiveness of the nonwoven fabric seems to be related to the crystallinity of the polymer, but a clear mechanism is not clear, and it is considered that a smaller amount of crystal components is preferable. When the non-woven fabric of the present invention is produced from the long-fiber non-woven fabric, it depends on the polymer composition, but when the spinning speed exceeds 5000 m / min, a tendency for the adhesiveness to decrease is observed, and preferably 4500 m / min or less. . The spinning speed may be obtained by directly measuring the fiber moving speed by the laser Doppler method or the like, but can also be obtained by converting from the single hole discharge amount and the product fiber diameter. Even if the spinning speed is lower than 100 m / min, there is no problem in solvent adhesion, but it becomes unstable during spinning such as yarn breakage.

  Moreover, it is preferable that a nonwoven fabric forms the crimping | compression-bonding part of a fiber by the embossing roll or flat calender process whose area rate is 5% or more at the temperature between 40-200 degreeC. A preferable pressure-bonding area ratio is more preferably 8% or more, and particularly preferably 15% or more. The area of the crimping part needs to be 5% or more. If the area is too small, peeling in the nonwoven fabric layer tends to occur, which is not preferable. The higher the area ratio, the better the adhesiveness, but the bulkiness of the nonwoven fabric is lost, so it is necessary to adopt an appropriate area ratio as required. If the processing temperature is lower than 40 ° C., the non-woven fabric properties may be changed due to the influence of room temperature, which is not preferable. On the other hand, if the processing temperature is 200 ° C. or higher, the nonwoven fabric tends to shrink more than necessary, which may cause a problem in dimensional stability. Although depending on the processing speed, the preferable processing temperature is 50 to 180 ° C., particularly preferably 50 to 100 ° C.

In the present invention, the nonwoven fabric preferably has a filling rate between 0.05 and 0.5. When the filling rate is less than 0.05, even if the adhesive strength between different nonwoven fabrics is high, peeling between layers inside the nonwoven fabric is caused, so that the bonding strength becomes small, which is not preferable. Moreover, the problem that the nonwoven fabric strength is too small or fuzzing easily occurs easily. Within the scope of the inventor's investigation, the adhesive strength tends to increase by increasing the filling rate. However, if the filling rate is greater than 0.5, the film tends to become harder and the texture tends to be easily broken by bending.
The nonwoven fabric preferably has a thickness of 0.05 to 1 mm, particularly preferably 0.08 to 0.3 mm. If the thickness is smaller than 0.05 mm, the bonding area of the fibers becomes small and it becomes difficult to obtain a desired bonding strength. On the other hand, if it is thicker than 1 mm, the amount of the solvent used is excessive, or the time required for evaporation is required, so that high-speed workability is impaired.

  In the present invention, the nonwoven fabric preferably shrinks by 2 to 60% at least in one direction at a dry heat shrinkage of 100 ° C., more preferably 3 to 50%. The shrinkage of the nonwoven fabric can be controlled by adjusting the polymer composition and the draw ratio during molding.

  The shrinkage anisotropy, which is a difference between an arbitrary direction of the nonwoven fabric and a direction perpendicular thereto, is excellent in handling at the time of use when the difference in the dry heat shrinkage at 100 ° C. is 5% or more. Preferably it is 10% or more, more preferably 20% or more. Further, from the viewpoint of handleability, process controllability, etc., the shrinkage rate in the direction of small shrinkage is preferably 30% or less, more preferably 20% or less, still more preferably 10% or less, and the shrinkage rate in the direction of large shrinkage is 80% or less, more preferably 70% or less.

  In the case of bonding a nonwoven fabric, it can be achieved by causing the fibers to swell and contact. From the viewpoint of high-speed adhesiveness, the solvent to be swollen is preferably 1,3 dioxolane, a mixed solution with an organic solvent compatible with 1,3 dioxolane, or a mixed solution with tetrahydrofuran or an organic solvent compatible with tetrahydrofuran. preferable. By using these solvents, high-speed workability of 20 to 200 m / min can be achieved.

  It is also preferable to attach a film having solvent adhesiveness to the nonwoven fabric. In this case, the thickness of the film is preferably 5 to 70 μm, particularly preferably 10 to 60 μm. If the thickness is less than 5 μm, there is a problem that the sheet is torn or wrinkled during the process. On the other hand, when it is thicker than 70 μm, there is a tendency that the texture becomes stiff, and wrinkles tend to occur during shrinkage. The film suitably used in the present invention is a film having shrinkage anisotropy, and is a film in which the difference in 100 ° C. dry heat shrinkage rate in one direction and the direction orthogonal thereto is different by 5% or more. Due to this shrinkage anisotropy, for example, when a laminated body is combined with a container as a heat insulating material, the shrinkage in the direction perpendicular to the container can be made larger than the shrinkage in the longitudinal direction of the container. Workability is improved. Moreover, also when providing a heat insulating material continuously with a roll etc. on a tube, control of a process becomes easy by making shrinkage | contraction of a longitudinal direction small.

  In the present invention, as a method of laminating and bonding the nonwoven fabric and the film, any method such as a usual dry or wet adhesive method, a heat-heat bonding method, an extrusion laminating method may be used. In particular, when using a polymer whose shrinkage rate can be controlled without performing a stretching operation in a subsequent step, such as a block copolymer polyester comprising a hard segment and a soft segment, the film thickness is 5 to 50 μm. Thus, the extrusion laminating method is one of the preferred forms because the process is simplified. In some cases, it is possible to control the shrinkage rate by stretching the laminated product or conversely shrinking it in the width direction by heat treatment.

  A packaging material, a heat insulating material, or the like made of the nonwoven fabric of the present invention alone or a laminate in which a film and a nonwoven fabric are laminated is attached (composited) to the container so as to cover at least a part of the container. When this heat insulating material is combined with a container or the like, it is possible to attach it with an adhesive, but it becomes difficult to remove the heat insulating material after use, or the recyclability is reduced by including a foreign substance called an adhesive. It is easy to cause problems. In the present invention, it is preferable that the container is covered with a heat insulating material or the like and is contracted to improve the adhesion with the container so as to be combined mainly by mechanical restraining force or frictional force.

  The shrinkage treatment temperature for combining the nonwoven fabric with the container is appropriately selected depending on the production process, but positioning with the container that is preliminarily shrunk at a relatively low temperature such as around 50 to 120 ° C. Therefore, it is preferable to perform the main shrinkage treatment for the next contact. By this method, it is possible to prevent misalignment of the printing surface and print distortion. The shrinkage in the longitudinal direction at the preshrinkage temperature of the heat insulating material or the like is preferably less than 1%. In order to control the shrinkage rate, it is important to select the polymer composition and the stretching and heat treatment conditions. The fiber is drawn at an appropriate draw ratio and deformation rate as required. It is also one of preferred embodiments that heat setting is performed at a temperature in the vicinity of the temperature so that the shrinkage does not occur below the pre-shrinkage temperature.

  In the case of applying a film to the nonwoven fabric of the present invention and applying it to a container, when the film is used with a resin such as block copolymer polyester or polyurethane, the main container is to cover at least a part of the plastic bottle or metal container. If it is fixed by shrinkage treatment, it becomes a dew condensation-preventing cold storage container. Also, when used in combination with a part of a container that holds a liquid or solid at about 40 ° C. or higher, such as a plastic bottle, a metal container, a paper or plastic cup, an instant noodle container, an alcoholic beverage container, etc. It can be set as a heat insulation container with.

  By shrinking the nonwoven fabric of the present invention, a plurality of small containers and objects such as luggage can be fixed and packaged together.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these at all.
The measuring method used in the present invention is as follows.
(Dry heat shrinkage)
Samples were cut into 20 cm squares and allowed to stand in a thermostat controlled at a temperature of 100 ° C. for 15 minutes, and then the shrinkage in the vertical and horizontal directions was measured.
(Thickness)
The thickness under a load of 7 g / cm ² was measured with a 2 cm peacock thickness gauge.

(Joint strength)
The non-woven fabrics were overlapped so as to overlap by 10 mm, and two tetrahydrofurans were applied to the width of about 3 mm with a cotton swab at an interval of 4 mm for adhesion. A rectangular sample was cut out so that the length of the joint surface was 15 mm, and the shear peel strength was measured.

(Example 1)
A resin comprising 100% terephthalic acid as the acid component and ethylene glycol (55 mol%) and neopentylglycol (45 mol%) as the alcohol component is made into a non-woven fabric at a spinning speed of 3800 m / min by the spunbond method. A sheet having a basis weight of 15 g / m ² was obtained. The resulting nonwoven fabric is embossed and calendered with an area ratio of 28% at a processing speed of 20 m / min at 50 ° C., thereby a nonwoven fabric having a thickness of 0.08 mm and a filling factor of 0.14 (calculated assuming a polymer density of 1.34). (Vertical and horizontal shrinkage ratio: vertical 22%, horizontal 16%). When the bonding strength of the obtained nonwoven fabric was measured, the adhesive surface was peeled off due to material destruction under a load of about 310 g.

(Example 2)
A heat shrink film (Space Clean SC-L, thickness 60 μm) manufactured by Toyobo Co., Ltd. was bonded to the nonwoven fabric of Example 1 with an ester resin by a dry lamination method. The laminated nonwoven fabric and the film were overlapped to measure the bonding strength. The bonding strength was sufficient at about 470 g. When a cylindrical state is created and covered with an aluminum bottle and then contracted, it is possible to uniformly adhere to the bottle, and it is considered that it can be suitably used as a heat insulating material.

(Example 3)
A resin composed of 100% terephthalic acid as an acid component and ethylene glycol (60 mol%) and cyclohexanedimethanol (40 mol%) as an alcohol component is made into a non-woven fabric by a spunbond method at a spinning speed of 3800 m / min. A sheet having a basis weight of 30 g / m ² was obtained. The obtained nonwoven fabric is plain calendered at 80 ° C. and a processing speed of 20 m / min to obtain a nonwoven fabric having a thickness of 0.07 mm and a filling rate of 0.32 (calculated assuming a polymer density of 1.34) (longitudinal and lateral shrinkage ratio: 31% in length and 18% in width). When the bonding strength of the obtained nonwoven fabric was measured, the adhesive surface peeled off due to material destruction under a load of about 440 g. When the offset gravure surface printing was performed, the printed surface was clearly displayed.

(Comparative Example 1)
The bonding strength of the nonwoven fabric of Example 1 was measured without emboss calendering. The thickness of the nonwoven fabric was 0.25 mm, and the filling rate was 0.04. Peeling occurs at the interface in the nonwoven fabric layer, and the bonding strength is as low as about 135 g.

(Comparative Example 2)
In Example 3, the nonwoven fabric was obtained on the same conditions except the fiber diameter of the nonwoven fabric being 35 micrometers. Although it was tried to measure the bonding strength, the adhesive strength is as small as about 205 g, and the use is considered to be considerably restricted.
When offset gravure surface printing was performed, fading was observed on the printed surface, which was a problem.

(Reference Example 1)
A spunbonded nonwoven fabric was prepared in the same manner as in Example 1, but the spinning speed was equivalent to 5200 m / min. Although the yarn breakage occurred frequently, a place where there was no problem was selected and embossed calendar treatment was performed to create a nonwoven fabric having the same thickness and filling rate as in Example 1. When the bonding strength between the nonwoven fabrics was measured, it was as low as about 190 g, and the use was considered to be considerably restricted.

(Reference Example 2)
A nonwoven fabric was obtained in the same manner as in Example 1 except that the material was polyethylene terephthalate. I tried to measure the bonding strength, but it did not adhere at all. The dry heat shrinkage was 0.5% in length and 0.1% in width.

The present invention relates to a nonwoven fabric that can be bonded to each other or to a sheet-like material such as a nonwoven fabric with a solvent and a method for producing the same, and is useful for a nonwoven fabric that can easily follow the form of an object by heat shrinkage. In particular, the nonwoven fabric of the present invention is bonded to a part of a container holding a liquid or solid having a temperature of about 40 ° C. or higher, such as a plastic bottle, a metal container, a paper or plastic cup, an instant noodle container, an alcoholic beverage container, etc. It can be used for a non-woven fabric having a heat insulating property capable of preventing burns. It can also be used as a non-woven fabric for fixing or packaging a plurality of objects such as containers and luggage by shrinking. In these applications, it is possible to easily wrap an object by making the nonwoven fabric into a tube shape or bag shape in advance, and it is difficult to tear by tearing etc. like a single film and has high cushioning properties. Useful.
Moreover, the nonwoven fabric of this invention is excellent in thermoformability, and is suitable for the use which utilized the characteristic excellent in printing suitability by selecting appropriate manufacturing conditions.

Claims (2)

A solvent-swelling fiber having a fiber diameter of 0.5 to 30 μm and made of a polyester resin copolymerized with neopentyl glycol or cyclohexanedimethanol as at least a part of an alcohol component has a fiber filling ratio of 0.05 to 0.5 . nonwoven thickness at 0.05 to 1.0 mm, solvent bondable nonwoven bonding area nonwoven is 5% or more. A solvent-swelling fiber having a fiber diameter of 0.5 to 30 μm comprising a polyester-based resin copolymerized with neopentyl glycol or cyclohexanedimethanol as at least a part of an alcohol component is spun at a spinning speed of 100 to 5000 m / min. A solvent-bondable non-woven fabric characterized in that the non-woven fabric obtained by spinning and then forming a crimped portion of the fiber by an embossing roll or flat calendering with an area ratio of 5% or more at a temperature between 40 and 200 degrees Production method.