JP2007105984A - Manufacturing method of protective film for glass and protective film for glass manufactured thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a protective film for glass capable of being laminated even to glass having an uneven surface such as ground glass or template glass with high adhesive strength and not causing the protrusion of an adhesive or the like. <P>SOLUTION: An adhesive layer 20, which is formed by laminating the adhesives different in molecular weight, is provided on one side of a base material 10 comprising a resin film and low-molecular weight adhesive layers 21 and 22 comprising the adhesives relatively low in molecular weight are arranged on the lamination side of the adhesive layer 20 to the base material 10 and the adhesive side to glass 30. A polymeric adhesive layer 23 comprising an adhesive relatively high in molecular weight with respect to the adhesive layers 21, 22 and (22') is arranged between the low molecular weight layers 21, 22 and (22'). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reinforced film that is used by being attached to a window glass such as a building such as a house or a vehicle, and more particularly suitably for a glass having an uneven surface such as a flat template glass or polished glass. With regard to the method of manufacturing a protective film for glass to be used, it is suitable not only for flat template glass but also for glass with an uneven surface, such as glass with wire, for purposes such as decoration and crime prevention. It is related with the manufacturing method of the protective film for glass which can be adapted, and the protective film for glass manufactured by this method.

  For example, in crimes such as burial, vandalism, and robbery, there are many cases where the window glass is broken and penetrates into the inside of the building. For example, a part of the glass fitted in an aluminum sash is broken to remove it from the damaged part. The door frame is locked, for example, the crescent lock is unlocked to enter the room or the like (hereinafter, for convenience of explanation, a window glass of a house or the like is illustrated) Explain).

  In this way, as a defensive measure against intrusion into the room that is performed by breaking the window glass, a resin film called “glass protective film” is attached to the indoor surface of the window glass to strengthen the window glass. However, even when the glass is hit with a hammer or the like, it is processed so that the glass cannot be easily broken.

  In this way, sticking the glass protective film to the window glass is an effective means of crime prevention, but the surface of the window glass is frosted for the purpose of blocking the line of sight from the outside or for a decorative effect. Many are also used that have surface irregularities such as polished glass and template glass with an irregular pattern on the surface.

  Therefore, even if it tries to stick the protective film for glass as mentioned above to the window glass, the follow-up property of the adhesive to the uneven surface of the glass is bad, and it peels off without obtaining the desired adhesion strength. The glass could not be tempered to the required strength, and further, air was collected between the glass and the protective film for glass, and the appearance was poor.

  As a protective film for glass for the purpose of sticking to glass having such an uneven surface, the adhesive material layer 20 formed on the back surface of the polycarbonate film as the substrate 10 has a relatively thick thickness of 150 to 200 μm. As a protective film for glass (see Patent Document 1: FIG. 2 (A)) with improved adhesion to the uneven surface, and double-sided tape 20 ′ to be attached to the surface film 10 ′, both sides of the acrylic foam 24 are acrylic. The one in which the pressure-sensitive adhesive layers 21 ′ and 22 ′ are formed has been proposed (see Patent Document 2: FIG. 2B).

Prior art document information of the present invention includes the following.
Japanese Patent Laid-Open No. 2005-180068 JP 2004-155092 A

  The pressure-sensitive adhesive is a resin that has viscoelasticity at room temperature and flows due to pressure contact with the adherend to bring about an adhesive force. The adhesive force is exhibited by the fluidity of the pressure-sensitive adhesive.

  Therefore, in the protective film for glass provided with the adhesive layer 20 in which the acrylic adhesive is formed much thicker than the conventional product, like the protective film 1 for glass described in Patent Document 1 described above, Even when the unevenness of the surface of the glass 30 is large due to the thickness of the pressure-sensitive adhesive layer 20, the pressure-sensitive adhesive layer 20 is adapted to the unevenness and exhibits an adhesive force (column “0012” in Patent Document 1).

  However, on the other hand, such an improvement in adhesive strength is obtained by the fluidity of the pressure-sensitive adhesive. When the thickness of the pressure-sensitive adhesive layer 20 is increased as described above, the flow-adhesive pressure is increased accordingly. The amount of agent also increases.

  Therefore, when the protective film for glass 1 is cut, the adhesive in the cross section flows, and the adhesive sticks to the blade of the cutting machine when the film is formed. As a result, frequent maintenance of the cutter is required, and adverse effects such as a deviation in dimensions during cutting are brought about.

  Further, when the thickness of the pressure-sensitive adhesive layer 20 is increased as described above, it takes time to dry the pressure-sensitive adhesive layer 20 and the productivity is lowered.

  On the other hand, in the invention described in Patent Document 2, an acrylic foam 24 is interposed in the intermediate layer as a member corresponding to the pressure-sensitive adhesive layer 20 in Patent Document 1, and the acrylic pressure-sensitive adhesive layer is formed on both surfaces of the acrylic foam 24. A double-sided tape 20 ′ formed with 21 ′ and 22 ′ is used.

  As described above, the acrylic foam 24 having deformability but not fluidity is interposed between the adhesive layers, whereby the acrylic foam 24 is deformed with respect to the unevenness of the glass 30 surface, and the uneven surface of the glass is exposed. While exhibiting followability, the pressure-sensitive adhesive layers 21 ′ and 22 ′ can be formed relatively thin, so that the pressure-sensitive adhesive as described above can be prevented.

  However, the acrylic foam 24 provided on the double-sided tape 20 'has deformability, but does not have fluidity. Therefore, when the thickness of the pressure-sensitive adhesive layer is increased as in the invention described in Patent Document 1 described above. In comparison, the adhesive strength decreases.

  That is, in the pressure-sensitive adhesive layer 20 formed of only the pressure-sensitive adhesive, since the pressure-sensitive adhesive layer 20 as a whole is formed of a flowable pressure-sensitive adhesive, it is pressed and adhered to the uneven surface of the glass 30. However, once the pressure-sensitive adhesive enters the irregularities of the glass, the pressure-sensitive adhesive exhibits a stable and strong adhesive force in this shape [see FIG. 2 (A)], but the invention described in Patent Document 2 As described above, when the acrylic foam 24 is interposed to form the double-sided tape 20 ′, the acrylic foam 24 is deformed according to the uneven shape of the glass 30, but it is difficult to deform into a shape that completely matches the uneven shape of the glass 30. Even if the pressure-sensitive adhesive layer 22 ′ enters the irregularities on the glass surface, it is difficult for the adhesive to reach the bottom of the irregularities.

  In addition, since the adhesive layer 22 ′ is applied with a force to return to the original flat shape by the restoring force of the acrylic foam 24, the adhesive layer 22 ′ is lifted from the concave portion of the glass 30, and the adhesive force is reduced. [Refer to FIG. 2B].

  Thus, if the adhesive strength of the glass protective film 1 is insufficient, even if the glass protective film 1 is attached to the window glass, the strength of the window glass cannot be improved to the intended level. Moreover, it peels after sticking, or air and water enter between glass and the protective film for glass, etc., and the following problems are accompanied.

  In particular, the above-mentioned polished glass and stencil glass are used for the purpose of blocking the field of view from the outside, and are therefore often used for bathroom windows. However, as described above, the glass surface and the adhesive layer 21 ' If there is even a slight gap between the glass surface and water in the winter season or in the bathroom, condensation will enter the glass surface and the adhesive layer, and the glass protective film 1 will be separated from or peeled off from the glass surface. It penetrates more easily and peels off, and the effect of the protective film for glass is lost.

  Thus, in the conventional protective film for glass, when the thickness of the pressure-sensitive adhesive layer is increased in order to improve the adhesion to the uneven surface, the adhesive force can be maintained, but the pressure-sensitive adhesive layer protrudes, etc. On the other hand, when acrylic foam or the like is interposed between the adhesive layers as a base material in order to prevent such protrusion, there is a problem that the adhesive force is reduced due to its restoring force. There is no film that can be applied to a protective film for glass that can solve these problems simultaneously.

  Therefore, the present invention can be applied to a glass having an uneven surface such as polished glass or template glass with a high adhesive force, and also reduces productivity and pressure-sensitive adhesive as in the case of thickly applying a pressure-sensitive adhesive. It aims at providing the manufacturing method of the protective film for glass which does not produce problems, such as a protrusion, and the film by this method.

In order to achieve the above object, the method for producing the protective film for glass 1 of the present invention comprises:
The release agent is coated with the polymer adhesive or a solution thereof using a kiss roll coater, gravure coater, knife coater, reverse roll coater, etc. so that the thickness when dried is 10 μm, and the temperature is 60 to 120 ° C. The polymer adhesive layer 23 is formed by drying.

  In addition, a low molecular pressure adhesive or a solution thereof is applied to release paper with a kiss roll coater, gravure coater, knife coater, reverse roll coater, etc. so that the thickness when dried is 70 μm, and the temperature is 60 to 120 ° C. It is dried to form the low molecular adhesion layer 21.

  Similarly, the low molecular adhesion layer 22 is formed. Meanwhile, the polymer adhesive layer 23 is laminated between the low molecular adhesive layers 21 and 22 while peeling the release paper. The release paper of the low molecular adhesive layers 21 and 22 is left.

  On the other hand, a low molecular pressure-sensitive adhesive or a solution thereof is applied to a PET film as the base material 10 with a kiss roll coater, gravure coater, knife coater, reverse roll coater or the like so as to have a thickness of 40 μm when dried. It is dried at a temperature of 0 ° C., and another low molecular adhesive layer 22 ′ is formed on the substrate 10 and prepared.

  Then, it comprises a step of polymerizing and laminating the low molecular adhesive layer 22 on the substrate 10 side while removing the release paper of the low molecular adhesive layer 22 in which the other low molecular adhesive layer 22 ′ is laminated on the polymer adhesive layer 23 ( Claim 1).

  The average molecular weight of the low molecular adhesive layer including other low molecular adhesive layers on the substrate 10 side is 100,000 to 3,000,000, preferably 200,000 to 2,000,000, and the average molecular weight of the polymer adhesive layer is 800,000 to 8,000,000, preferably 1,000,000 to 5,000,000. (Claim 2).

  Further, the total thickness of the pressure-sensitive adhesive layer 20 can be filled with the depth of the unevenness (about 150 μm) on the uneven surface of the template glass. From the viewpoint of preventing the occurrence of a decrease in productivity and the sticking out of the adhesive at the time of cutting, it is 150 to 450 μm, more preferably 160 to 250 μm, and the thickness of the polymer adhesive layer 23 is 1 to 100 μm, 10 to 50 μm, more preferably 5 to 50 μm is more preferable (Claim 3), the low molecular adhesive layer 22 on the substrate 10 (PET film) side, and another low molecular adhesive layer 22 ′. The thickness of each is 50 to 145 μm, preferably 70 to 120 μm. On the glass 30 side, 49 to 145 μm, preferably 70 to 120 μm, and 80 to 110 μm are more suitable.

  The polymer adhesive layer 23, the low molecular adhesive layers 21, 22, and the other low molecular adhesive layers 22 'can all be formed of an acrylic resin.

  As the substrate 10, a polyester film having a thickness of 100 to 500 μm, preferably 150 to 400 μm can be used.

  And this invention protective film is comprised by the said manufacturing method, It is characterized by the above-mentioned (Claim 7).

  As described above, the low-molecular pressure-sensitive adhesive layers 21 and 22 and 22 ′ disposed on the polyester film substrate 10 side of the pressure-sensitive adhesive layer 20 and the bonding side to the glass 30 surface, and these low-molecular pressure-sensitive adhesive layers 21. And the adhesive layer 20 is formed by laminating the polymer adhesive layer 23 disposed between 22 (and 22 '), so that the molecular weight is high, and therefore compared with the low molecular adhesive layers 21, 22, 22'. Thus, the flow-out of the pressure-sensitive adhesive was suppressed by the polymer pressure-sensitive adhesive layer 23 having poor fluidity, and as a result, it was possible to effectively prevent the pressure-sensitive adhesive from protruding.

  On the other hand, although the polymer adhesive layer 23 formed in the middle of the adhesive layer 20 is inferior in fluidity as compared with the low molecular adhesive layers 21, 22, 22 ′ as described above, it itself has fluidity. Because it is composed of an adhesive that has an adhesive, it flows into the irregularities on the affixed surface when it is pressed or adhered to glass with irregular surfaces, such as polished glass or template glass, and once flows into the irregularities In order to stabilize in that state, it was possible to provide the protective film 1 for glass exhibiting high adhesiveness.

  Next, embodiments of the present invention will be described below.

Overall Configuration The protective film for glass of the present invention is a protective film for glass 1 having a total thickness of 250 to 950 μm in which an adhesive layer 20 is formed on one side of a base material 10 made of a resin film as shown in FIG.

Resin film (base material)
In the protective film 1 for glass of the present invention, the resin film used as the base material 10 is made of various known materials as long as it improves the strength of the glass adhered to such an extent that a crime prevention effect can be expected. Although it can be used, in this embodiment, a polyester film is used.

In the glass protective film 1 of the present invention, as in the glass protective film introduced as the above-mentioned Patent Document 1, for example, a polycarbonate substrate can be used, but polycarbonate has a linear expansion coefficient of about 7 ×. 10 ⁻⁵ / ° C is large, and therefore the problem is that it floats from the glass surface due to changes in temperature due to the difference from the linear expansion coefficient of glass (about 0.8 to 1 × 10 ⁻⁵ / ° C), and is easily peeled off. Therefore, in this embodiment, a polyester film having a lower linear expansion coefficient than that of the polycarbonate is used.

  Polyester resins (saturated polyester) include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), poly 1,4 cyclohexyldimethylene terephthalate (PCT), and polyethylene naphthalate (PEN). The type is not limited as long as a film including the above can be obtained, but in this embodiment, PET of these is used as a base material.

  The PET film used as the base material 10 in the present embodiment uses a hard coat treatment on the surface (outside surface) opposite to the surface on which the adhesive layer 20 described later is laminated. .

  The thickness of the PET film to be used is determined by how much strength is imparted to the glass, that is, the degree of safety as the protective film 1 for glass. As an example, the thickness of this PET film is: The thickness is 100 to 500 μm, preferably 150 to 400 μm. It can be said that the greater the thickness, the higher the safety.

The pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 20 provided in the protective film 1 for glass of the present invention can prevent protrusion during cutting or the like while maintaining high followability to the uneven surface of the glass 30, that is, fluidity. It is formed by laminating adhesives with different molecular weights so as to have shape retention.

  In order to impart the above-described properties to the pressure-sensitive adhesive layer 20, in the glass protective film 1 of the present invention, the pressure-sensitive adhesive layer 20 is laminated on the base material 10 and adhered to the glass surface 30. On the side, the low molecular pressure-sensitive adhesive layers 21, 22, 22 ′ composed of a pressure-sensitive adhesive having a relatively low molecular weight are disposed, and the low-molecular pressure-sensitive adhesive layer 21 is disposed between the low-molecular pressure-sensitive adhesive layers 21, 22, 22 ′. , 22, 22 ′, the molecular weight of the pressure-sensitive adhesive is made different in the thickness direction of the pressure-sensitive adhesive layer 20 by arranging the polymer pressure-sensitive adhesive layer 23 composed of a pressure-sensitive adhesive having a high molecular weight. Yes.

  The total thickness of the pressure-sensitive adhesive layer 20 can fill the unevenness depth (about 150 μm) on the uneven surface of the template glass, while the productivity due to the longer drying time associated with the excessive thickness. From the viewpoint of preventing the occurrence of the decrease in the pressure and the occurrence of the sticking out of the adhesive at the time of cutting, it is preferably 150 to 450 μm, more preferably 160 to 250 μm, and in this embodiment 200 μm.

  The low molecular adhesion layers 21, 22, 22 ′ and the polymer adhesion layer 23 described above are balanced at the interface, and as a result, the molecular weight at the interface portion is balanced over time. Disappears, the pressure-sensitive adhesive layer 20 is integrated as a whole, and has a “molecular gradient” in which the molecular weight changes with a predetermined gradient in the thickness direction.

  Due to such disappearance of the interface, it is impossible to clearly distinguish the low-molecular and high-molecular pressure-sensitive adhesive layers. This will be described as “molecular adhesive layer” and “polymer adhesive layer”.

Polymer adhesive layer The adhesive (resin) constituting the polymer adhesive layer 23 uses a resin having a high molecular weight in comparison with the adhesive constituting the low molecular adhesive layers 21, 22, and 22 'described later. To do.

  As the resin used as the polymer adhesive layer 23, various known materials used as an adhesive can be used. Examples of such resins are as follows.

(1) Natural rubber
(2) synthetic rubber (for example, styrene-butadiene, polyisobutylene, isoprene, etc.),
(3) Acrylic resin (eg, 2-ethylhexyl acrylate, butyl acrylate, ethyl acrylate polymer),
(4) Olefin resin (eg, polystyrene-ethylene / butylene copolymer, polyethylene, copolymer of polystyrene-ethylene-propylene, etc.),
(5) Silicone resin (for example, vinyl polydimethylsiloxane copolymer, vinyltrichlorosilane-alkoxysilane copolymer, etc.),
(6) Urethane resins [for example, those obtained by reaction of polyisocyanate and polyol (polyester polyol, polyester polyol / polylactone polyol, etc.)],
(7) Polyester resin,
(8) saturated polyester,
(9) Unsaturated polyester.

  The polymer adhesive layer can be preferably formed of an acrylic resin.

  As the acrylic resin, for example, one obtained by polymerizing one or more of the following monomers by solution polymerization, bulk emulsion polymerization, suspension polymerization or the like can be used, and acrylic acid, methacrylic acid, alkyl groups are used. For example, alkyl acrylate, alkyl methacrylate (eg, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic, substituted or unsubstituted and having 1 to 20 carbon atoms Isononyl acid, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, dimethylaminoethyl methacrylate), vinyl acetate, acrylonitrile, acrylamide, styrene, vinylidene chloride, itaconic acid, acrylamide, methylol acrylamide, methacryl Glycidyl acid, maleic anhydride and the like can be used.

  Preferably, the polymer adhesive layer is formed of a water-based acrylic emulsion resin.

  The polymer adhesive layer is prepared by blending one or more raw material monomers or polymers with additives that are blended as desired, and polymerized by solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, etc. It can be formed by an extrusion method such as a coater drying method, a T-die method, an inflation method, or a casting method thereof.

  In addition, you may contain additives, such as an anti-aging agent, a heat conductive agent, a heat shrinkage prevention agent, a flame retardant, in a polymer adhesion layer.

Low molecular adhesive layer The adhesive (resin) constituting the low molecular adhesive layers 21, 22, 22 ′ is the polymer on both the lamination side with respect to the base material (PET film) 10 and the adhesive side with respect to the glass 30. A resin having a low molecular weight relative to the resin constituting the adhesive layer 23 is used, and various known resins that can normally be used as “adhesives” can be used.

  An example of such a resin is as follows.

(1) natural rubber,
(2) Synthetic rubber (eg, styrene-butadiene, polyisobutylene, isoprene, etc.),
(3) Acrylic resin (for example, methyl (meth) acrylate, ethyl (methyl) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc.),
(4) Olefin resin (eg, polyethylene, polypropylene, etc.),
(5) Silicone resin (for example, siloxane / trichlorosilane, alcoholosilane),
(6) Urethane resins (for example, polyester polyols, polycarbonates, polyol polyols, polyalkylene polyols, etc.).

  The low molecular pressure-sensitive adhesive layer is particularly preferably formed of an acrylic resin. As this acrylic resin, one or more of the monomers listed as the acrylic resin in the same manner as the above-mentioned high-molecular pressure-sensitive adhesive layer are used for solution polymerization and bulk polymerization. Those obtained by polymerization by emulsion polymerization, suspension polymerization or the like can be used.

  Additives such as tackifiers, softeners, fillers, anti-aging agents, cross-linking agents and the like can be included in the resin constituting the low-molecular pressure-sensitive adhesive layer as desired.

  The following are mentioned as said tackifier added as an additive as needed.

(1) Rosin (e.g. rosin, gumcord rosin, modified rosin, rosin ester),
(2) terpene phenol resin,
(3) terpene resin,
(4) Synthetic petroleum resins (for example, isoprene, cyclopentadiene, 1,3-pentadiene, 1-pentene copolymer, 2-pentene, dicyclopentadiene copolymer, 1,3-pentadiene-based resin, indene, styrene, methylindene , Α-methylstyrene copolymer),
(5) phenolic resin,
(6) xylene resin,
(7) alicyclic petroleum resin,
(8) Coumarone indene resin,
(9) Styrenic resin,
(10) Dicyclopentadiene resin.

  Moreover, as said additive, it can select and use from the additive quoted as an additive added to the above-mentioned polymer adhesion layer.

Combination Conditions of Low Molecular Adhesive Layer and Polymer Adhesive Layer The adhesive layer 20 in the protective film 1 for glass of the present invention is a resin material constituting the low molecular adhesive layers 21, 22, 22 ′ and the polymer adhesive layer 23 described above. A combination satisfying the following conditions is selected and laminated from the pressure-sensitive adhesive comprising:

  In the following description, for the low molecular adhesive layers 21, 22, and 22 ′, the low molecular adhesive layers 22 and 22 ′ on the substrate 20 side and the low molecular adhesive layer 21 on the glass 30 side are the same adhesive. Although it demonstrates as what comprises with an agent, within the range which satisfy | fills the following conditions, you may comprise the base material side low molecular adhesion layers 22 and 22 'and the glass side low molecular adhesion layer 21 with a different adhesive. .

Material The resin constituting the above-mentioned polymer adhesive layer 23 and the resin constituting the low-molecular adhesive layers 21, 22, 22 ′ may be formed by different types of resins, but preferably a monomer is used. It is formed of a common resin.

  In the present embodiment, the polymer adhesive layer 23 and the low molecular adhesive layers 21, 22, 22 'are both made of an acrylic resin.

Molecular weight A pressure-sensitive adhesive is a resin that exhibits viscoelasticity at room temperature and flows by pressure contact with an adherend to exert an adhesive force. The relationship between the fluidity and molecular weight of a resin is that it is fluid when the molecular weight is high. The fluidity improves as the molecular weight decreases.

  In the protective film 1 for glass of the present invention, paying attention to the properties of such a resin, a pressure-sensitive adhesive having a relatively low molecular weight on the lamination side with respect to the base material (PET film) 20 and the adhesion side with respect to the glass 30. The low molecular pressure-sensitive adhesive layers 21, 22, and 22 ′ are provided to improve fluidity and give high adhesive force, and the molecular weight is relatively high between the low molecular pressure-sensitive adhesive layers 21, 22, and 22 ′. By providing the polymer adhesive layer 23 that has fluidity but is inferior to the low-molecular adhesive layers 21, 22, and 22 ', the entire pressure-sensitive adhesive layer 20 is retained to the extent that adhesion is not impaired. The adhesive is not protruded even when the glass protective film 1 is cut or the like.

  In order to satisfy the conflicting demands of fluidity and shape retention of the pressure-sensitive adhesive layer 20, the glass protective film 1 according to the present invention includes the low-molecular pressure-sensitive adhesive layers 21, 22, 22 ′. As an example of the pressure-sensitive adhesive, the average molecular weight is preferably 200,000 to 2,000,000 as an example, and the polymer pressure-sensitive adhesive layer 23 is configured with respect to the molecular weight of the resin constituting the low-molecular pressure-sensitive adhesive layer 21, 22, 22 ′. The molecular weight of the resin is set to 800,000 to 8,000,000, preferably 1,000,000 to 5,000,000, and the molecular weight of the resin constituting the polymer adhesive layer 23 is relatively high.

thickness
Total thickness of the pressure-sensitive adhesive layer The total thickness of the pressure-sensitive adhesive layer 20 is such that the unevenness depth on the uneven surface of the template glass is about 150 μm, and the total thickness is 150 μm or more so that it can be filled inside the unevenness. If it is too thick, it is preferably 450 μm or less, more preferably 160 to 250 μm, because of the stickiness of the adhesive at the time of cutting and the decrease in productivity due to the time required for drying, etc., more preferably 160 to 250 μm. Is 200 μm.

Thickness of polymer adhesive layer As the polymer adhesive layer 23 becomes thicker, the fluidity of the adhesive layer 20 as a whole is lowered to reduce the adhesive force. On the other hand, when the polymer adhesive layer 23 is too thin, it is retained in the adhesive layer 20. Since the formability cannot be imparted and the sticking out of the adhesive cannot be prevented, the thickness of the polymer adhesive layer 23 should be 1 to 100 μm, preferably 10 to 50 μm, more preferably 10 to 15 μm. preferable.

  In this embodiment in which the total thickness of the adhesive layer 20 is 200 μm, the thickness of the polymer adhesive layer 23 is 10 μm in this embodiment.

Low-molecular adhesive layer On the other hand, the thickness of the low-molecular adhesive layers 21, 22, 22 ′ is 50 to 145 μm, preferably 70 to 120 μm, more preferably 80 to 110 μm on the substrate (PET film) 10 side. is there. In the present embodiment in which the total thickness of the pressure-sensitive adhesive layer is 200 μm, it is 80 μm.

  Further, on the side of the surface to be adhered to the glass, it is more preferable that the thickness is 50 to 145 μm, preferably 70 to 120 μm, 80 to 110 μm. In the present embodiment in which the total thickness of the pressure-sensitive adhesive layer is 200 μm, it is preferably 70 to 120 μm, and in this embodiment it is 110 μm.

In the protective film 1 for glass of the present invention configured as described above, the pressure-sensitive adhesive layer 20 is formed by laminating the low-molecular pressure-sensitive adhesive layers 21, 22, 22 ′ and the polymer pressure-sensitive adhesive layer 23 as described above. Therefore, the polymer adhesive layer 23 inferior to the low molecular adhesive layers 21, 22, and 22 ′ in fluidity acts as if it were a base material provided on the adhesive layer 20. This prevents the adhesive from sticking out when the glass protective film 1 is cut.

  However, although the polymer adhesive layer 23 itself is inferior in fluidity to the low molecular adhesive layers 21, 22, and 22 ′, it functions as an adhesive having fluidity. Even when it is fluidized by pressure welding and attached to a glass having an uneven surface such as polished glass or template glass, it exhibits high adhesiveness due to its fluidity.

  Thus, when the pressure-sensitive adhesive layer 20 is formed, the pressure-sensitive adhesive layer is adjusted by appropriately adjusting the molecular weight ratio between the low-molecular pressure-sensitive adhesive layers 21, 22, 22 ′ and the polymer pressure-sensitive adhesive layer 23 and the thicknesses of both layers. 20, it becomes possible to obtain an adhesive layer having a predetermined molecular gradient that exhibits both the fluidity and shape-retaining properties required by the present invention.

The production method of the present invention will be described according to the embodiment.
Polymer adhesive layer 23
The release agent is coated with the polymer adhesive or a solution thereof using a kiss roll coater, gravure coater, knife coater, reverse roll coater, etc. so that the thickness when dried is 10 μm, and the temperature is 60 to 120 ° C. The polymer adhesive layer 23 is formed by drying.

Low molecular adhesive layers 21, 22
Apply low-molecular-weight adhesive or its solution to release paper with a kiss roll coater, gravure coater, knife coater, reverse roll coater, etc. so that the thickness when dried is 70 μm, and dry at a temperature of 60 to 120 ° C. , Low molecular adhesion layers 21 and 22 are formed, respectively.

Lamination of Polymer Adhesive Layer 23 and Low Molecular Adhesive Layers 21 and 22 The polymer adhesive layer 23 is polymerized and laminated between the low molecular adhesive layers 21 and 22 while peeling the release paper of the polymer adhesive layer 23. The release paper of the low molecular adhesive layers 21 and 22 is left.

Substrate 10 and other low molecular adhesion layers 22 '
A low molecular pressure-sensitive adhesive or a solution thereof is applied to a PET film as a base material 10 with a kiss roll coater, a gravure coater, a knife coater, a reverse roll coater or the like so as to have a thickness of 50 μm at the time of drying. Drying at a temperature forms a low molecular adhesion layer 22 'on the substrate.

Lamination of the base material 10 and the polymer adhesive layer 23 The low molecular adhesive layer 22 ′ on the base material side of the base material 10 is removed while removing the release paper of the low molecular adhesive layer 22 of the polymer adhesive layer 23. Polymerization is laminated.

  The protective film for glass of the present invention may be in the form of a tape or a sheet that is coated with a release material such as a PET film and release paper or a release paper or release film. In this case, following the above-described winding process, there may be a process of slitting to a desired size tape or sheet width according to the application.

  The manufacturing method is generally the same as that described in 5. above. (Hereinafter the same).

Test Example 1: Molecular Weight Change and Adhesive Strength-Shape Retention Characteristics Confirmation Test [Test Conditions]
The structure of each layer of the used protective film for glass is as follows.
Base material: PET film (thickness: 188 μm)
Low molecular adhesion layer: Acrylic resin (Molecular weight: 200,000, Thickness: PET side 110μm, Adhered body side 70μm)
Polymer adhesive layer: Acrylic resin (thickness 10μm)

〔Test method〕
In the above protective film for glass, the molecular weight of the polymer pressure-sensitive adhesive layer was changed, and the change in adhesive strength and the shape retention of the pressure-sensitive adhesive layer (existence of protrusion when cut) were confirmed. The protrusions were confirmed by visual inspection, and the case where the protrusion was confirmed was evaluated as “×”, and the case where the protrusion was not confirmed was evaluated as “◯”.

  In the table below, “low molecular weight only (200 μm)” is a comparative example in which a low molecular pressure-sensitive adhesive alone was applied to a substrate with a thickness of 200 μm to form a pressure-sensitive adhesive layer, and the molecular weight ratio “1: 1”. Is a comparative example in which a low molecular adhesive is applied to a substrate in three portions of 80 μm, 10 μm and 110 μm, and the molecular weight of each layer is the same.

  “Initial adhesive strength” in the table below is a standard condition in which a specimen cut to a width of 25 mm is bonded to an adherend (SUS plate, smooth glass, template glass) and reciprocated twice with a 2 kg roll. The result is a result of a 180 ° peel test at a speed of 300 mm / min after being left for 30 minutes, and “normal adhesive strength” is the above “initial adhesive strength” except that the standing time is 24 hours. It measured by the same method.

  As a result of the above, the glass protective film having the pressure-sensitive adhesive layer formed only of the low-molecular pressure-sensitive adhesive exhibited high adhesive force, but in both cases, the pressure-sensitive adhesive protruded from the cut surface.

  In contrast, in the pressure-sensitive adhesive layer in the protective film for glass of the present application, as the difference between the molecular weight of the polymer pressure-sensitive adhesive layer and the molecular weight of the low-molecular pressure-sensitive adhesive layer increases, a decrease in adhesive force was confirmed. Even when the molecular weight is less than 4 times that of the low-molecular pressure-sensitive adhesive layer, it is possible to obtain the necessary adhesive strength as a protective film for glass. It was.

  In addition, when the molecular weight of the polymer adhesive layer is 4 times or more that of the low molecular adhesive layer, the sticking out of the adhesive at the cut portion when the protective film for glass is cut is not so much as to cause a practical problem. In addition, the protrusions could not be confirmed visually.

  Therefore, the molecular weight ratio of the low-molecular adhesive layer and the polymer adhesive layer is 1: 4 to 1:25 in order to obtain an adhesive layer that does not cause adhesive sticking without reducing the adhesive strength. This was confirmed by the above experiment.

Test Example 2: Change in thickness and adhesive property of polymer adhesive layer [Test conditions]
The structure of each layer of the used protective film for glass is as follows.
Base material: PET film (thickness: 188 μm)
Low molecular adhesion layer: Acrylic resin (Molecular weight: 200,000)
Polymer adhesive layer: Acrylic resin (Molecular weight: 1,000,000)

〔Test method〕
Using the above protective film for glass, the thickness of the polymer adhesive layer is changed, and the total thickness of the adhesive layer is adjusted to 200 μm to change the adhesive force and maintain the adhesive layer. Changes in formability (presence or absence of protrusion during cutting) were confirmed.

  The protrusions were confirmed visually, and the case where the protrusions were confirmed was evaluated as “×”, and the case where the protrusions were not confirmed was evaluated as “◯”.

  Note that the measurement methods of “initial adhesive strength” and “normal adhesive strength” in the table below are the same as in Test Example 1.

  As a result of the above, in the above test example in which the total thickness of the pressure-sensitive adhesive layer was 200 μm, it was possible to prevent the pressure-sensitive adhesive from protruding while ensuring the necessary adhesive force by setting the polymer pressure-sensitive adhesive layer to 10 to 15 μm. .

  Therefore, from the above experiments, it is confirmed that when the thickness of the polymer pressure-sensitive adhesive layer is in the range of 5 to 10% with respect to the total thickness of the pressure-sensitive adhesive layer, both adhesive force and shape retention can be achieved. did it.

Test Example 3: Change in thickness and adhesive property of low molecular adhesive layer (attachment side) [Test conditions]
The structure of each layer of the used protective film for glass is as follows.
Base material: PET film (thickness: 188 μm)
Low molecular adhesion layer: Acrylic resin (Molecular weight: 200,000)
Polymer adhesive layer: Acrylic resin (Molecular weight: 1,000,000, thickness: 10μm)

〔Test method〕
Using the above protective film for glass, the thickness of the low-molecular pressure-sensitive adhesive layer is changed within the range of the total thickness of the pressure-sensitive adhesive layer to 200 μm, and the adhesive force changes and the shape-retaining property of the pressure-sensitive adhesive layer (extrusion at the time of cutting) The change in the presence or absence of was confirmed.

  In addition, the protrusion was confirmed visually, and the case where the protrusion was confirmed was evaluated as “×”, and the case where the protrusion was not confirmed was evaluated as “◯”.

  Further, the measurement methods of “initial adhesive strength” and “normal adhesive strength” in the table below are the same as those in Test Example 1.

  As a result of the above, by setting the low molecular pressure-sensitive adhesive layer on the adherend side to 70 μm or more, the necessary adhesive force can be secured, and by setting it to less than 130 μm, it is possible to prevent the adhesive from sticking out. did it.

  In particular, when the thickness of the adhesion-side low molecular pressure-sensitive adhesive layer is in the range of 70 to 110 μm, extremely high adhesiveness can be secured, but no sticking out of the adhesive was confirmed.

  Therefore, from the above experiment, it was confirmed that when the thickness of the low molecular pressure-sensitive adhesive layer and the total thickness of the pressure-sensitive adhesive layer are set within a certain range, both adhesive force and shape retention can be achieved.

Test Example 4: Submerged test [Test conditions]
The structure of each layer of the used protective film for glass is as follows.
Base material: PET film (thickness: 188 μm)
Low molecular adhesion layer: Acrylic resin (Molecular weight: 200,000)
Polymer adhesive layer: Acrylic resin (Molecular weight: 1,000,000, thickness: 10μm)

〔Test method〕
A glass protective film with a different low-molecular adhesive layer thickness on the deposition side (glass side) (total thickness of the adhesive layer is 200μm for all), and the rugged surface of the stencil glass (vertical roughness 160) ~ 180μm), water was applied with a dropper from the upper end of the protective film for glass, and “X” indicates that water was immersed between the glass and the protective film for glass, and “○” indicates that water was not observed. ".

  As a result, when the thickness of the low molecular adhesive layer on the glass side was 45 μm or less, water immersion was confirmed between the glass and the protective film for glass, and when the thickness was 50 μm or more, water immersion could not be confirmed.

  Therefore, it was confirmed that the adhesive completely penetrated into the irregularities on the glass surface when the thickness of the low molecular adhesive layer on the glass surface side was 50 μm or more.

Test Example 5: Change in adhesive layer thickness and adhesive force change characteristics The results of changing the adhesive layer thickness by changing the adhesive layer thickness are shown below.
〔Test conditions〕
The structure of each layer of the used protective film for glass is as follows.
Polystyrene substrate: PET film (thickness: 188 μm)
Low molecular adhesion layer: Acrylic resin (Molecular weight: 200,000)
Polymer adhesive layer: Acrylic resin (Molecular weight: 1,000,000)

〔Test method〕
Using the above protective film for glass, the total thickness of the pressure-sensitive adhesive layer was changed, and the change in adhesive strength (initial adhesive strength) was confirmed.

  The following table shows the results of tests conducted on three test pieces, n1 to n3, and the average value calculated.

  The adhesive strength was measured as before.

  Adhesive strength of about 1,300 g / 25 mm is necessary to exert the effect as a protective film for glass. However, when the total thickness of the pressure-sensitive adhesive layer is less than 150 μm, the adhesive strength, particularly to the template glass, is required. It was confirmed that the adhesive strength was less than the above value.

  Such a decrease in adhesive force is that the uneven depth on the uneven surface of a typical template glass is about 150 μm maximum, so if the total thickness of the adhesive layer is less than 150 μm, It is considered that the pressure-sensitive adhesive cannot sufficiently enter the irregularities, and as a result, the necessary adhesive force cannot be obtained.

  On the other hand, as the thickness of the pressure-sensitive adhesive layer increases, the adhesive force increases. However, if the thickness of the pressure-sensitive adhesive layer is excessively increased, it takes time to dry in the manufacturing process, and the pressure-sensitive adhesive protrudes during cutting. Therefore, the total thickness of the pressure-sensitive adhesive layer is preferably 150 to 300 μm, more preferably 160 to 250 μm.

The cross-sectional enlarged view of the protective film for glass of this invention. It is explanatory drawing of the conventional protective film for glass, (A) is what applied the adhesive thickly and formed the adhesive layer, (B) provides a base material (acrylic foam) between the adhesive layers Example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Protective film for glass 10 Base material 10 'Surface film 20 Adhesive layer 20' Double-stick tape 21 Low molecular adhesive layer (base material side)
22,22 'Low molecular adhesion layer (glass side)
21 ', 22' adhesive layer 23 polymer adhesive layer 24 acrylic foam 30 glass

Claims (7)

A method for producing a protective film for glass, comprising the following steps:
Applying a polymer adhesive to the release paper and drying to form a polymer adhesive layer;
Applying a low molecular adhesive to the release paper and drying to form two low molecular adhesive layers,
Polymerizing and laminating the polymer adhesive layer between the low molecular adhesive layers;
Applying and drying a low molecular adhesive on the substrate, forming another low molecular adhesive layer on the substrate side, and preparing,
A step of polymerizing and laminating another low molecular pressure-sensitive adhesive layer formed on the base material on the low molecular pressure-sensitive adhesive layer laminated on the polymer pressure-sensitive adhesive layer.   The average molecular weight of the low molecular adhesive layer including the other low molecular adhesive layers is 100,000 to 3,000,000, preferably 200,000 to 2,000,000, and the average molecular weight of the high molecular adhesive layer is 800,000 to 8,000,000, preferably 1,000,000 to 5,000,000. The method for producing a protective film for glass according to claim 1.   The total thickness of the adhesive layer is 150 to 450 μm, preferably 150 to 350 μm, more preferably 160 to 250 μm, and the thickness of the polymer adhesive layer is 1 to 100 μm, preferably 10 to 50 μm, more preferably, The method for producing a protective film for glass according to claim 1 or 2, wherein the thickness is 10 to 15 µm.   The thickness of the low molecular adhesive layer on the glass side is 49 to 145 μm, preferably 70 to 120 μm and 80 to 110 μm, and the low molecular adhesive layer and the other low molecular adhesive layer on the substrate side are 50 to The method for producing a protective film for glass according to claim 1 or 2, wherein the thickness is 145 µm, preferably 70 to 120 µm.   5. The protective film for glass according to claim 1, wherein each of the polymer adhesive layer and the low molecular adhesive layer including the other low molecular adhesive layer is formed of an acrylic resin. Production method.   The method for producing a protective film for glass according to any one of claims 1 to 5, wherein the substrate is made of a polyester film and has a thickness of 100 to 500 µm, preferably 150 to 400 µm.   A protective film for glass, which is made of a resin film produced by the production method according to any one of claims 1 to 6, which is used by being attached to glass.

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