CN101181947A - Packaging film - Google Patents

Abstract

The invention provides a packaged film. The double-axle package tensile film with unseal bands overlapped along the width direction of the film can be tore straightly and stably along the unseal band even when tearing the unseal band along an inclined direction. The package film takes a double-axle package tensile propylene resin film with unseal bands overlapped along the direction which is parallel to the width direction of the film. The tensile rate in the length direction of the film is below 170%. Besides, the unseal bands are overlapped along the width direction of the double-axle package tensile propylene resin film.

Description

Film for packaging

Technical field

The present invention relates to the novel package film that constitutes by the biaxial stretch-formed polypropylene resin film.Specifically, the invention provides the film for packaging that directivity is significantly improved of tearing that Width at the biaxial stretch-formed polypropylene resin film (below, also slightly count TD sometimes) is provided with Kaifeng band, TD.

Background technology

The film for packaging that particularly constitutes by plastic film by the biaxial stretch-formed polypropylene resin film, according to the aspect of its intensity, packing character, economy, be used to the packing of daily groceries such as hobby such as food such as sandwich, rice dumpling, toffee, cigarette commodity packaging, CD, DVD, magnetic tape cartridge etc., various packaged bodies.

Usually, by heat seal and fusing sealing etc.,, then, pack packaged body with above-mentioned film for packaging bag.Yet, in the time of also will being implemented in taking-up as the packaged body of content, can tearing the part that packaging bag need be torn easily and tear this packaging bag such time.

For example, in the above-mentioned film for packaging, numerous motions of disposing Kaifeng band (also claiming " tear off ribbon ") for tearing film easily are suggested (referring to Patent Document 1～4).Generally speaking, constituting by the biaxial stretch-formed polypropylene resin film under the situation of film for packaging, from this film end, the length direction of this film (below, sometimes also MD slightly) the above-mentioned Kaifeng of lamination band in the end of above-mentioned film, clipping the Kaifeng band grooving (otch) is set.Dispose the packaging body of this Kaifeng band, can from the grooving of film for packaging, tear film for packaging (packaging body) by pullling this Kaifeng band along this Kaifeng band.In addition, constitute the base material film that be with in Kaifeng, have the film of high tensile owing to use usually, so can not disconnect in the process of Kaifeng, this Kaifeng band also has the effect that prevents to cut mistake.

, state in the use in the film for packaging of biaxial stretch-formed polypropylene resin film,, require along the TD vertical, the layer of the above-mentioned Kaifeng of lamination band sometimes with the MD direction of prior art according to the use form of film.

Yet, distinguish:,, produce unstable this problem of directivity of tearing of so-called TD if use general-duty biaxial stretch-formed polypropylene resin film in the situation that the Kaifeng band is set along the TD of film as mentioned above like that.

For example, pin the packaging bag (packaging body) that constitutes by above-mentioned film for packaging at hand of no use, pull the situation of Kaifeng band, the situation that the speed that pullling breaks a seal is with is excessive etc., cause a kind of departing from by the direction of Kaifeng band guiding, thereby the situation that content (packaged body) is scurried out takes place along the state of obliquely tearing this film.Particularly as the packaging bag of sandwich, the Kaifeng distance of Kaifeng band is grown (about about 80～120mm), and the situation that content is soft, the tight sense of imperceptible sometimes this content and packaging body, when tearing the Kaifeng band, packaging body self moves very knifeedge, the tendency that has the problems referred to above frequently to take place.

And, even in the biaxial stretch-formed polypropylene resin film, also there is this phenomenon, particularly in lamination low melting point, low-crystalline, non-crystalline polyolefin resin situation as the biaxial stretch-formed lamination polypropylene resin film of heat seal type of heat sealing layer, tear directivity and become unstable because of the softness characteristics of the resin that constitutes this heat sealing layer makes, having the above-mentioned phenomenon of easier generation is the tendency of the problems referred to above.

Patent documentation 1: the spy opens flat 3-289459 communique

Patent documentation 2: open flat 6-42689 communique in fact

Patent documentation 3: No. 3014696 communique of registration utility model

Patent documentation 4: the spy opens the 2005-53508 communique

Summary of the invention

Therefore, the objective of the invention is to: be provided in the film for packaging that makes by the biaxial stretch-formed polypropylene resin film, tear the very good film for packaging of directivity by what the Kaifeng band caused when the TD of this film is provided with the Kaifeng band.

In order to achieve the above object, the inventor waits and has carried out in-depth study repeatedly.It found that: for the tensile elongation that reduces MD to below the specific value, carry out the biaxial stretch-formed polypropylene resin film of molecular orientation to heavens, by TD lamination the Kaifeng band is arranged, make thus by this Kaifeng and be with the film for packaging that directivity is significantly improved of tearing that causes along the direction vertical with the direction of this molecular orientation.And, also find: even biaxial stretch-formed polypropylene resin film lamination heat sealing layer also can be brought into play above-mentioned effect fully, thereby finish the present invention.

Promptly, the invention provides a kind of film for packaging, it is characterized in that: the tensile elongation of length direction is below 170%, constitute and constitute by having at least through the biaxial stretch-formed polypropylene resin film of biaxial stretch-formed substrate layer by polypropylene-based resin, and, along the Width lamination of this biaxial stretch-formed polypropylene resin film Kaifeng band and constitute.

In the above-mentioned film for packaging, the tensile elongation of biaxial stretch-formed polypropylene resin film preferable width direction is 40～90%.Because the tensile elongation of Width satisfies above-mentioned scope, can constitute the biaxial stretch-formed polypropylene resin film of mechanical strength balance excellence, so enlarge its purposes, therefore preferred.

In addition, in the above-mentioned film for packaging, the biaxial stretch-formed polypropylene resin film preferably is being made of polypropylene-based resin and is being lower than the heat sealing layer that the polyolefin resin of this polypropylene-based resin constitutes through at least one lamination of biaxial stretch-formed substrate layer by fusing point.Biaxial stretch-formed polypropylene resin film by this structure constitutes owing to become the film for packaging of formability excellence, uses so can be used as the film for packaging of various uses.

Further say, in the above-mentioned film for packaging, in order to bring into play effect of the present invention more significantly, the gross thickness of above-mentioned heat sealing layer (under the situation of the two sides of substrate layer lamination heat sealing layer, being the summation of the thickness of the heat sealing layer on two sides) be preferably the biaxial stretch-formed polypropylene resin film thickness 0.8～25%.

The present invention also provides by the film formed sandwich packaging bag of above-mentioned packaging.

The effect of invention

Film for packaging of the present invention can solve the problem that the unstable such prior art of tearing property of TD exists, and can stably tear along above-mentioned Kaifeng band.In addition, at least the biaxial stretch-formed polypropylene resin film superimposed layer Kaifeng band of heat sealing layer is being arranged and constituting under the situation of such structure at a superimposed layer of substrate layer, owing to there is heat sealing layer, in the film of prior art, be easy to generate unstable this problem of tearing property of TD especially, even but the present invention is in the film for packaging of state like this, also can stably tear along above-mentioned Kaifeng band.

Therefore, the present invention can remove the restriction to the direction of lamination Kaifeng band in the film for packaging that uses the biaxial stretch-formed polypropylene resin film.That is, in any case can satisfy the requirement of situation about being with along TD lamination Kaifeng because of the restriction needs of print gap, print direction, packaged configuration or raising packaging bag yield etc.Its result can improve the degree of utilization of biaxial stretch-formed polypropylene resin film in packaging field, and is very big to the contribution degree of industrial development.

Description of drawings

Fig. 1 is arranged at the birds-eye view of the state on the ground paper for sample in the operation of tearing property of expression evaluation.

The front view of Fig. 2 when sample is fixed in chuck in the operation of expression tearing property evaluation.

The lateral plan of Fig. 3 when sample is fixed in chuck in the operation of expression tearing property evaluation.

The birds-eye view of the sample of Fig. 4 after for tensile test in the operation of expression tearing property evaluation.

Fig. 5 is the skeleton diagram of an example of the sandwich packaging bag of expression use film for packaging of the present invention.

Nomenclature

The A datum line

A ' datum line

B breaks a seal mouthful

C chuck (top)

C ' chuck (below)

The E adhesive tape

The F tear trace

F ' tear trace

The position that G begins to tear

The position that G ' begins to tear

The H contact

I tears distance

The J ground paper

The K band that breaks a seal

The biaxial stretch-formed stack membrane of L

The grooving that M is provided with in the sandwich packaging bag

The Kaifeng band that N is provided with in the sandwich packaging bag

The specific embodiment

The invention provides the film for packaging that constitutes and have the Kaifeng band by polypropylene-based resin along having at least through the TD lamination of the biaxial stretch-formed polypropylene resin film of biaxial stretch-formed substrate layer.And the tensile elongation of the length direction of the present invention by making this biaxial stretch-formed polypropylene resin film is below 170%, can utilize this Kaifeng band along TD straight line and tearing film stably, improves " tearing directivity ".

[constituting the polypropylene-based resin of substrate layer]

Film for packaging of the present invention constitutes and constitutes through the biaxial stretch-formed polypropylene resin film of biaxial stretch-formed substrate layer by having at least by polypropylene-based resin.

As this polypropylene-based resin, so long as adopt following biaxial stretch-formed method, have and to reach the MD tensile elongation and get final product, generally speaking, use the resin of the polypropylene-based resin that contains 50～100 quality % at the crystalline polypropylene-based resin of this degree below 170%.If the above-mentioned polypropylene-based resin of illustration particularly then can be enumerated Noblen, be derived from propylene-alpha-olefin copolymers, propylene-ethylene-1-butene terpolymers and these the compound of the monomeric unit less than 30 quality % of the alpha-olefin beyond the propylene.In addition, above-mentioned alpha-olefin for example can be enumerated ethene, 1-butylene, 1-amylene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4-methyl-1-pentene etc.Say that further above-mentioned copolymer can be in random copolymers, periodic copolymer, the graft copolymer any.In addition, following heat sealing layer is made of the polyolefin resin that fusing point is lower than the polypropylene-based resin that constitutes base material, constitute the fusing point of the polypropylene-based resin of substrate layer of the present invention, mix using under the situation of above-mentioned polypropylene-based resin, is benchmark with the fusing point of the big polypropylene-based resin of cooperation ratio.In addition, under the identical situation of cooperation ratio, be benchmark with the high polypropylene-based resin of fusing point.

Among the present invention, even among above-mentioned polypropylene-based resin, in order to make the more excellent film of film and Kaifeng property, preferably use Noblen, ethylene contents be 0.2～5.0 quality % the propylene-ethylene random copolymers, to make ethylene contents through modulation be the Noblen of 0.2～5.0 quality % and the compound of propylene-ethylene random copolymers.

In addition, in order to improve the function of the biaxial stretch-formed polypropylene resin film that makes, can in above-mentioned polypropylene-based resin, add resin as follows.If the resin of these interpolations of illustration can be enumerated low density polyethylene (LDPE), straight chain shape low density polyethylene (LDPE), medium density polyethylene, high density polyethylene (HDPE), polybutene, petroleum resin, ethene-alpha-olefin copolymer, 1-1-butene-alpha-olefin copolymers, various elastic bodys etc.Make film by in polypropylene-based resin, adding above-mentioned resin, can improve easy stretchability, high transparent, highly moistureproof, additive-treated oil and ooze out the delustringization of the easy property improved of promotion property, roughness of surface, film, easily make film, heat seal and because of the effects such as surfaction of Corona discharge Treatment etc.

Moreover the melt mass flow rate of above-mentioned polypropylene-based resin if consider the system film, is 0.5～15.0g/10 minute at 230 ℃ preferably then, most preferably is 1.0～10.0g/10 minute.In addition, for the melt mass flow rate that is added with the polypropylene-based resin that improves above-mentioned dynamopathic resin, it is 1.0～20.0g/10 minute preferably at 230 ℃.

[biaxial stretch-formed polypropylene resin film]

Film for packaging of the present invention constitutes and constitutes through the biaxial stretch-formed polypropylene resin film of biaxial stretch-formed substrate layer by having at least by above-mentioned polypropylene-based resin.The substrate layer of this biaxial stretch-formed polypropylene resin film uses above-mentioned illustrative arbitrary polypropylene-based resin, and both available individual layer constitutes, and also can use the multilayer that is made of the diverse resin resin different with additive to constitute according to purpose.If illustration is with the example that multilayer constitutes particularly, can be set forth in the main stor(e)y superimposed layer that constitutes by polypropylene-based resin by the top layer that has cooperated additive-treated oil polypropylene-based resin to constitute, as the example of substrate layer with specific function.In addition, heat sealing layer described later is made of the low-melting polyolefin resin of fusing point than the polypropylene-based resin that constitutes substrate layer, but, in the polypropylene-based resin that constitutes substrate layer, be benchmark with the fusing point of the big polypropylene-based resin of cooperation ratio constituting with multilayer under the situation of substrate layer.Also having, under the identical situation of the cooperation ratio of the polypropylene-based resin that constitutes substrate layer, is benchmark with the high polypropylene-based resin of fusing point.

Among the present invention, can make above-mentioned substrate layer contain known additive.Moreover (for example, under the situation with main stor(e)y and top layer formation) can certainly make each layer contain known additive under the situation that constitutes substrate layer with multilayer.If the known additive of illustration can be enumerated antioxidant, lubricant, antiblocking agent, antidim compound, chlorine agent for capturing, antistatic agent, nucleating agent etc. particularly.Particularly in the purposes of packing sandwich and other foods, use the situation of film for packaging of the present invention, owing to produce sometimes because of forming vaporific this problem to the film dewfall after the packing, so preferably add antidim compound and antistatic agent.

Wherein, in order to make the excellent antifog property of film for packaging performance of the present invention, preferably make above-mentioned substrate layer contain the antidim compound of 0.5～1.5 quality %.Constituting by main stor(e)y and top layer under the situation of substrate layer, the antidim compound that preferred main stor(e)y contains is 0.5～1.5 quality %, and the gross thickness on top layer (exist on the two sides under the situation on top layer, be meant the summation of thickness on the top layer on two sides) is 3～20% of the thickness of substrate layer.Say further, preferably increase a side of antifog property, on the substrate layer of this side, implement surface treatments such as corona treatment in expectation.In addition, film for packaging of the present invention, in situation about constituting by the biaxial stretch-formed polypropylene resin film that only constitutes with the substrate layer of lamination heat sealing layer not, perhaps any situation in the situation that the biaxial stretch-formed polypropylene resin film that heat sealing layer is arranged by lamination constitutes, in order to bring into play excellent antifog property, the cooperation ratio of preferred antidim compound satisfies above-mentioned scope.

Among the present invention, also can in the scope that does not influence effect of the present invention, known functional layer be set, for example bonding coat, gas barrier layer, light shield layer, ultraviolet blocking layer etc. on the surface of substrate layer.

The maximum of film for packaging of the present invention is characterised in that, makes to have at least by above-mentioned polypropylene-based resin to constitute and be below 170%, to be preferably below 160% through the MD tensile elongation of the biaxial stretch-formed polypropylene resin film of biaxial stretch-formed substrate layer.That is, above-mentioned tensile elongation surpasses 170% biaxial stretch-formed polypropylene resin film, and shown in the comparative example described as follows, the tearing property reduction of TD when being torn by the Kaifeng band, is difficult to tear point-blank along this Kaifeng band.

In addition, be not particularly limited the lower limit of the tensile elongation of MD, if the productivity of considering, during as rerum natura of film for packaging etc., preferably the following of the tensile elongation of this MD is limited to 80%.

Usually, though the biaxial stretch-formed polypropylene resin film that in packing, uses, the character that has longitudinally and laterally all easily tear, when tearing this film for packaging, if exert oneself along oblique, the former state crustal inclination is torn.And the MD tensile elongation of the relevant biaxial stretch-formed polypropylene resin film that makes according to prior art generally surpasses 180%.At this biaxial stretch-formed polypropylene resin film superimposed layer the situation of heat sealing layer is arranged, special in the big situation of its thickness, exist tensile elongation further to become big tendency.

At above-mentioned tendency, the present invention uses the biaxial stretch-formed polypropylene resin film that the tensile elongation of MD is below 170%, molecule further is orientated along MD.

Like this, be below 170% by the MD tensile elongation that makes the biaxial stretch-formed polypropylene resin film, can improve the tearing property of TD that causes by following Kaifeng band significantly, can stablize and tearing film point-blank.

Though do not know still in the film for packaging of the present invention, utilize along the Kaifeng band of TD lamination and significantly improve the mechanism of tearing directivity that the inventor etc. infer as follows.Promptly, the MD tensile elongation that makes film is at the film for packaging of the present invention below 170%, the strand that constitutes the biaxial stretch-formed polypropylene resin film of this film for packaging is in the state that further is orientated along MD, and this molecule is in the state of orientation that can not extend again along MD.And utilize when tearing film for packaging perpendicular to the Kaifeng band of the direction lamination of above-mentioned orientation, on this film, apply shearing force, thus, the destruction of the strand of this part is taken place.Can infer: the strand that this Kaifeng band can not extend along MD by destruction again forms takes " the tearing " that is caused by the Kaifeng band as the leading factor, tears this film point-blank along this Kaifeng band.That is, can think: in order to be improved the direction of tearing of TD by the Kaifeng band, key is, does not reduce the peel strength of TD, and reduces the tensile elongation (becoming the state that strand can not extend along MD again) of MD.This mechanism, for example in expectation along under the situation of TD tearing film, the present film that further is orientated along TD with strand to tear mechanism different fully.

In the film for packaging of the present invention, the biaxial stretch-formed polypropylene resin film, though other rerum natura beyond the tensile elongation of MD is not particularly limited, as preferred rerum natura, the tensile elongation of preferred TD is 40～90%.In addition, most preferably the difference of the tensile elongation of the tensile elongation of MD and TD is 30～120%.By satisfying these rerum naturas, can in extensive use, use.

Say that further the pulling strengrth that preferably satisfies MD is more than the 150MPa, to be preferably 155～230MPa, and the pulling strengrth that preferably satisfies TD is more than the 200MPa, to be preferably 220～340MPa.

In addition, the birefringence of preferred MD and TD is below 0.01300.By making the biaxial stretch-formed polypropylene resin film satisfy these rerum naturas, can improve the direction of tearing of TD more.In addition, though this birefringent lower limit is not particularly limited,, be preferably 0.00050 if consider the rerum natura, system film etc. of film.

Above-mentioned birefringence makes the ratio of refraction of using up represent degree poor of the molecular orientation of MD in the face and TD.That is, with respect to the differently-oriented directivity in the face, the orientation of molecule is high more, and it is big more that the ratio of refraction of the light of this direction becomes.Here, the MD tensile elongation that need make biaxial stretch-formed polypropylene resin film of the present invention is below 170%, and molecule is compared with general biaxial-stretched polypropylene films, is in a kind of state that is orientated more to heavens along MD, thus, the difference of the orientation of MD and TD diminishes.Its result, the birefringence as the difference of the ratio of refraction of MD and TD becomes less than general biaxial-stretched polypropylene films.

Moreover, the thickness of the biaxial stretch-formed polypropylene resin film that constitutes film for packaging of the present invention is not particularly limited, but generally is preferably 15～80 μ m, be preferably 20～60 μ m especially.

In the film for packaging of the present invention, above-mentioned biaxial stretch-formed polypropylene resin film can be only to use the not film of the substrate layer formation of lamination heat sealing layer.This situation constitutes and is below 170% through biaxial stretch-formed substrate layer as the tensile elongation of the length direction of biaxial stretch-formed polypropylene resin film and this film as long as make by above-mentioned polypropylene-based resin.Simultaneously, preferably this film satisfies above-mentioned various rerum naturas (for example, the pulling strengrth of the tensile elongation of TD, MD, TD, birefraction, film thickness etc.).

In addition, film for packaging of the present invention, as long as the tensile elongation of the length direction of biaxial stretch-formed polypropylene resin film is below 170%, can constitute by biaxial stretch-formed polypropylene resin film at least one lamination heat sealing layer of substrate layer, wherein, this substrate layer is made of polypropylene-based resin, and this heat sealing layer is made of the polyolefin resin that fusing point is lower than this polypropylene-based resin.By at least one lamination heat sealing layer at above-mentioned substrate layer, 2 processing characteristics of film for packaging of the present invention are become well, can be used in the packing of various packaged bodies.Below, also will be designated as " biaxial stretch-formed lamination polypropylene resin film " sometimes at the biaxial stretch-formed polypropylene resin film of at least one lamination heat sealing layer of substrate layer.

Then, the heat sealing layer of this biaxial stretch-formed lamination polypropylene resin film and the polyolefin resin that constitutes heat sealing layer are described.

[heat sealing layer and the polyolefin resin that constitutes heat sealing layer]

In the packaging film of the present invention, be layered on the heat sealing layer of one side at least through biaxial stretch-formed substrate layer, can be according to packing comformability of packaged content and wrapping machine etc., consider that necessary heat-seal strength and heat seal welding begin temperature, suitably select the polyolefin resin of its thickness and formation.

Especially make the situation of sandwich adopting the heat seal method to process film for packaging of the present invention with packaging bag, preferably use heat-seal strength as more than the 2.5N/15mm, be preferably the biaxial stretch-formed lamination polypropylene resin film more than the 3.0N/15mm.Therefore, be applied to the situation of such use, preferably satisfying the polyolefin resin of above-mentioned heat-seal strength.

The polyolefin resin that constitutes heat sealing layer is the resin that fusing point is lower than the polypropylene-based resin that constitutes above-mentioned substrate layer.Preferred especially fusing point hangs down 15～60 ℃ resin than the fusing point of the polypropylene-based resin that constitutes above-mentioned substrate layer.If illustration constitutes the polyolefin resin of heat sealing layer particularly, can enumerate straight chain shape low density polyethylene (LDPE), be derived from propylene-alpha-olefin copolymers, propylene-ethylene-1-butene terpolymers and their compound of the monomeric unit less than 30 quality % of the alpha-olefin beyond the propylene.In addition, above-mentioned alpha-olefin for example can be enumerated ethene, 1-butylene, 1-amylene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4-methyl-1-pentene etc.Say that further above-mentioned copolymer can be in random copolymers, periodic copolymer, the graft copolymer any.Wherein, in order to make film and heat seal, the more excellent film of antifog property, preferably using fusing point is 100～130 ℃ straight chain shape low density polyethylene (LDPE), propylene-ethylene random copolymers, the propylene-ethylene-1-butene terpolymers that fusing point is 110～140 ℃.In addition, mix using the situation of these polyolefin resins, is benchmark with the fusing point of the big acrylic resin of cooperation ratio.Also having, in the identical situation of cooperation ratio, is benchmark with low-melting polypropylene-based resin.The situation of the heat sealing layer that is made of different polyolefin resins at the two sides of substrate layer lamination is a benchmark with the fusing point of the polyolefin resin that constitutes each heat sealing layer.

Above-mentioned heat sealing layer further provided additive-treated oils such as low temperature heat sealization, antidim compound ooze out the situation of function such as promotion property in expectation, preferably in the polyolefin resin that constitutes above-mentioned heat sealing layer, in the following ratio of 60 quality %, mix the low melting point, the low-crystalline elastic body that constitute by ethene-alpha-olefin, 1-1-butene-alpha-olefin copolymers etc.

In addition, the situation that above-mentioned heat sealing layer is further had the outward appearance of tarnish (matt) style in expectation, preferably in the polyolefin resin that constitutes above-mentioned heat sealing layer, suitably mix the non-resin that mixes that constitutes by low density polyethylene (LDPE), medium density polyethylene, high density polyethylene (HDPE), polybutene, polypropylene etc.

Among the present invention, can in heat sealing layer, not have and especially restrictedly add the illustrated additive of above-mentioned substrate layer.

In addition, constitute the said polyolefins resinoid of above-mentioned heat sealing layer, have and make antidim compound contained in the substrate layer ooze out into the effect on this heat sealing layer surface effectively, can provide fabulous antifog property this heat sealing layer surface.Therefore, film for packaging of the present invention can be suitable for purposes such as sandwich packaging bag.

For above-mentioned biaxial stretch-formed lamination polypropylene resin film,, can form heat sealing layer in the one side of substrate layer or the two sides of substrate layer according to the purposes of film for packaging.

In the film for packaging of the present invention, the gross thickness of the heat sealing layer of the biaxial stretch-formed lamination polypropylene resin film (situation that heat sealing layer is arranged at the two sides lamination, summation for the thickness of the heat sealing layer on two sides), be preferably 0.5～12.0 μ m, more preferably 0.5～10.0 μ m.

But, feature as film for packaging of the present invention, the tensile elongation of the MD of biaxial stretch-formed lamination polypropylene resin film, owing to depend primarily on the characteristic of above-mentioned substrate layer, so, can not reach the tensile elongation of target sometimes in the thickness of the heat sealing layer situation excessive with respect to the thickness of substrate layer.In other words, the tensile elongation of the MD of biaxial stretch-formed lamination polypropylene resin film is necessary for below 170%, if but heat sealing layer is too thick, can not satisfy this tensile elongation sometimes.

Can think: the tensile elongation of MD generally is subjected to lamination that very big influence of MD molecular orientation of the substrate layer of heat sealing layer arranged.Certainly, adopt the stretching process of the heat sealing layer of following coetrusion and online lamination (inlinelami) method lamination, along the draw direction orientation of two-axle draw direction or single shaft through two-axle stretching process or single shaft.But, certainly stretching as the final TD that stretches, need to set draft temperature and be the temperature that the resin of the formation substrate layer of the fusing point that fusing point is higher than the resin that constitutes heat sealing layer can stretch.Can think thus: under the stenter baking oven hot-cured heat treatment temperature of the final process that stretches as TD, relaxed the orientation of most molecules of the low-melting polyolefin resin that constitutes heat sealing layer especially.The heat sealing layer that the low-melting polyolefin resin that is relaxed by the orientation of molecule constitutes, the tensile elongation of heat sealing layer itself increases.Its result in the heat sealing layer situation blocked up with respect to substrate layer, becomes the result that the tensile elongation of MD also increases sometimes, hinders and tears directivity.

Therefore, the gross thickness of above-mentioned heat sealing layer preferably satisfy above-mentioned scope and limit its for all below 25% of thickness of biaxial stretch-formed lamination polypropylene resin film, be preferably 0.8～25%.

Secondly, illustrate that it is the rerum natura of biaxial stretch-formed lamination polypropylene resin film that lamination has the film of above-mentioned heat sealing layer.

[biaxial stretch-formed lamination polypropylene resin film]

Above-mentioned biaxial stretch-formed lamination polypropylene resin film can adopt following method, at least one lamination heat sealing layer through biaxial stretch-formed substrate layer.As the rerum natura of this biaxial stretch-formed lamination polypropylene resin film, as illustrated in the above-mentioned biaxial stretch-formed polypropylene resin film, the tensile elongation of MD is below 170%, to be preferably below 160%.That is, the tensile elongation of MD surpasses 170% biaxial stretch-formed lamination polypropylene resin film, and shown in the comparative example described as follows, the directivity of tearing of TD reduces, and when being torn by the Kaifeng band, is difficult to tear point-blank along this Kaifeng band.Lower limit to the tensile elongation of MD is not particularly limited, but consider productivity, as rerum natura of film for packaging etc., be preferably 80%.

In the film for packaging of the present invention, the pulling strengrth of TD tensile elongation, MD and the TD of biaxial stretch-formed lamination polypropylene resin film is not particularly limited, but, preferably satisfies the scope that in above-mentioned biaxial stretch-formed polypropylene resin film, illustrates as preferred rerum natura.Specifically, the tensile elongation of preferred TD is 40～90%.In addition, more preferably the difference of the tensile elongation of the tensile elongation of MD and TD is 60～120%.Say that further the pulling strengrth that preferably satisfies MD is more than the 150MPa, to be preferably 155～230MPa, the pulling strengrth of TD is more than the 200MPa, preferred 220～310MPa.

Moreover the MD of above-mentioned biaxial stretch-formed lamination polypropylene resin film and the birefringence of TD preferably become littler.Specifically, be preferably below 0.01100, more preferably below 0.01000.As mentioned above, this birefringence is the rerum natura of difference of the degree of the ratio of refraction of the using up orientation of representing MD in the face and TD.Here,, be necessary that making the tensile elongation of MD is below 170%, and the difference of the molecular orientation of MD and TD diminished that its result diminishes as the birefringence of the difference of the ratio of refraction of MD and TD for biaxial stretch-formed polypropylene resin film of the present invention.In addition, heat sealing layer as described above, molecule be difficult to the orientation.Therefore, the birefringence of above-mentioned biaxial stretch-formed lamination polypropylene resin film, littler than the birefringence of the above-mentioned biaxial stretch-formed polypropylene resin film of lamination heat sealing layer not.In addition, this birefringent lower limit is not particularly limited, if but consider the rerum natura, system film etc. of film, be preferably 0.00050.

In addition, the thickness of the biaxial stretch-formed lamination polypropylene resin film that constitutes film for packaging of the present invention is not particularly limited, but the ratio of the thickness of preferred heat sealing layer and thickness satisfies above-mentioned scope and be 15～80 μ m, be preferably 20～60 μ m especially.

[manufacture method of film]

Secondly, the manufacture method about the biaxial stretch-formed polypropylene resin film of above-mentioned explanation describes.The manufacture method of film is in the situation of lamination heat sealing layer and the situation of lamination heat sealing layer not, its manufacture method difference.The manufacture method of the biaxial stretch-formed polypropylene resin film that therefore, lamination heat sealing layer not is described at first, only constitutes by substrate layer.

[the not manufacture method of the film of lamination heat sealing layer]

Below Shuo Ming manufacture method is to make by above-mentioned polypropylene-based resin to constitute and be the manufacture method of this situation of biaxial stretch-formed polypropylene resin film through biaxial stretch-formed substrate layer.

In the film for packaging of the present invention, be not particularly limited for the manufacture method of the biaxial stretch-formed polypropylene resin film of lamination heat sealing layer not, but as preferable methods, can the following method of illustration.

That is, the preferred employing by the biaxial stretch-formed sheet material that is made of above-mentioned polypropylene-based resin one by one made the method through biaxial stretch-formed substrate layer.Most preferably in this is biaxial stretch-formed, along the method for MD stretching more than 5.5 times.

Not in the manufacture method of the biaxial stretch-formed polypropylene resin film of lamination heat sealing layer,, preferably stretch more than 5.5 times along MD for the tensile elongation of the MD that makes this film is below 170%.In addition, for the upper limit of the stretching ratio when MD stretches,, then be preferably 8.5 times if consider the rerum natura etc. of system film, film for packaging.

For the operation that stretches along MD, both can stretch more than 5.5 times with 1 stage, also can stretch more than 5.5 times with the multistage.Particularly stretch more than 5.5 times along MD, can stably make film with 2 stages that stretched, are generally multistage.In addition, in situation about stretching with the multistage, the MD stretching ratio that needs only as net result is that all MD stretching ratios are more than 5.5 times.

In addition, along in the stretching of TD, there is no particular limitation to its stretching ratio, but preferably stretch more than 8 times.Be set at more than 8 times by stretching ratio, can utilize the equilibrium with the stretching ratio of above-mentioned MD, make the high biaxial stretch-formed polypropylene resin film of thickness and precision TD.In order to make the higher film of thickness and precision, more preferably the stretching ratio of TD is more than 8.5 times.In addition, for the upper limit of the stretching ratio of TD,, then be preferably 13.0 times if consider the rerum natura etc. of system film, film for packaging.

Above-mentionedly stretch one by one, stretching be by the sheet material that will extrude by extruder after MD stretches, stretch and carry out along TD again.

Below, illustrate that it is the manufacture method of biaxial stretch-formed lamination polypropylene resin film that lamination has the film of above-mentioned heat sealing layer.

[manufacture method of biaxial stretch-formed lamination polypropylene resin film]

Manufacture method for the biaxial stretch-formed lamination polypropylene resin film that constitutes film for packaging of the present invention has no particular limits, but as preferable methods, can the following method of illustration.

That is, in the method for the biaxial stretch-formed one by one sheet material that is made of above-mentioned polypropylene-based resin, preferably among by the arbitrary process in the process of making film that stretches one by one, the lamination fusing point is lower than this method of polyolefin resin of this polypropylene-based resin.Most preferably above-mentioned biaxial stretch-formed one by one in, along stretch method more than 6 times of MD.By the lamination heat sealing layer, can improve the tensile elongation of MD, so preferably compare, can improve the method for the stretching of MD with the film of lamination heat sealing layer not.

In addition, polypropylene-based resin and polyolefin resin as raw material certainly use illustrative resin in the explanation of above-mentioned substrate layer and heat sealing layer.

In the manufacture method of biaxial stretch-formed lamination polypropylene resin film of the present invention,, preferably stretch more than 6 times along MD for the MD tensile elongation of the film that satisfies gained is below 170%.In addition, the upper limit when MD stretches if consider the rerum natura etc. of system film, film for packaging, then is preferably 8.5 times.

For the above-mentioned operation that stretches along MD, both can stretch more than 6 times with 1 stage, also can stretch more than 6 times with the multistage.Particularly stretch more than 6 times along MD, can stably make film with 2 stages that stretched, are generally multistage.In addition, in situation about stretching, as long as be that all MD stretching ratios are more than 6 times as the stretching ratio of the MD of net result with the multistage.

In addition, along in the stretching of TD, the restriction unqualified to its stretching ratio, but preferably stretch more than 8 times.Be set at more than 8 times by stretching ratio, can utilize the equilibrium with the stretching ratio of above-mentioned MD, make the high biaxial stretch-formed lamination polypropylene resin film of thickness and precision TD.In order to make the higher film of thickness and precision, more preferably the stretching ratio of TD is more than 8.5 times.In addition, the upper limit for the stretching ratio of TD if consider stable system film, the rerum natura of film for packaging etc., then is preferably 13.0 times.

Above-mentionedly stretch one by one, stretching be by the sheet material that will extrude by extruder after MD extends, stretch and carry out along TD.

In the manufacture method of biaxial stretch-formed lamination polypropylene resin film of the present invention,, can in above-mentioned arbitrary process in biaxial stretch-formed one by one, carry out for the formation of heat sealing layer.

At first, the situation that adopts online lay-up method is described.Adopt the T die methods, the final no stretched sheet that is used as substrate layer and is made of above-mentioned polypropylene-based resin is shaped.Then, utilize the velocity contrast of roller, this no stretched sheet is carried out the MD roller stretch, make the MD stretched sheet.Secondly, utilize the extruder that is provided with in addition,, extrude the polyolefin resin that constitutes heat sealing layer,, carry out the fusion lamination, make the lamination MD stretched sheet that lamination has heat sealing layer at the one or both sides of this MD stretched sheet by the T mould.Again secondly, this lamination MD stretched sheet is imported stenter, with the two ends that clip is clamped this lamination MD stretched sheet, in the stenter baking oven, a/s width carries out TD and stretches, and makes biaxial stretch-formed lamination polypropylene resin film.

Secondly, the situation that adopts coetrusion is described.Utilize the extruder more than 2, by the coextrusion mould, coextrusion is respectively from the above-mentioned polypropylene-based resin and the said polyolefins resinoid of each stream, on the no stretched sheet surface that is made of polypropylene-based resin, the shaping lamination has the no stretch laminate sheet material of the heat sealing layer that is made of polyolefin resin.Secondly, utilize the velocity contrast of roller, this no stretch laminate sheet material is carried out the MD roller stretch, make lamination MD stretched sheet.Then, this lamination MD stretched sheet is imported stenter, with the two ends that clip is clamped this lamination MD stretched sheet, in the stenter baking oven, a/s width carries out TD and stretches, and makes biaxial stretch-formed lamination polypropylene resin film.

In addition, also can make up above-mentioned two kinds of methods.For example, also can adopt above-mentioned coetrusion, make the lamination MD stretched sheet that heat sealing layer is only arranged at a lamination in advance.Then, adopt online lay-up method, one side (surface of substrate layer) the lamination heat sealing layer opposite with the heat sealing layer stromatolith of this lamination MD sheet material is formed in the lamination MD stretched sheet that two surperficial superimposed layers have heat sealing layer.Then, adopt above-mentioned TD drawing process, make the biaxial stretch-formed stack membrane that heat sealing layer is arranged at two surperficial laminations.

Adopt the situation of online lay-up method, constitute the sheet material of substrate layer, can consider to constitute the fusing point and the crystallinity of the resin of base material film, before MD stretches, fully carry out preheating for MD in advance stretches.Therefore, even the MD stretching ratio is more than 6 times, also can implement without a doubt.

And on the other hand, adopt the situation of coetrusion, because the fusing point of the polypropylene-based resin of formation substrate layer is different with the fusing point of the polyolefin resin that constitutes heat sealing layer, so form the sheet material that lamination has the different resin of fusing point.Therefore, stretch the MD preheating temperature that the dystectic polypropylene-based resin that needs setting to constitute substrate layer can stretch in order stably to carry out MD by high magnification.But, under this situation, surpass the fusing point of the polyolefin resin that constitutes heat sealing layer sometimes, cause this polyolefin resin to adhere to easily on MD preheat roll and the MD draw roll.In addition, take place easily to hinder in the sheet surface that constitutes heat sealing layer because of the stretching that the MD stretching causes.But,, can adopt following method for fear of the generation of these problems.

For example, only, at first, adopt coetrusion,, set temperature with the contacted preheating/draw roll of heat sealing layer according to the fusing point and the crystallinity of the polyolefin resin that constitutes heat sealing layer in the situation of single face lamination heat sealing layer.On the other hand, for the sheet face of the opposition side of lamination heat sealing layer not,, set temperature with the contacted preheating/draw roll of this sheet face according to the fusing point and the crystallinity of the resin that constitutes this sheet face.For example, if the sheet face of above-mentioned opposition side is a substrate layer,, the temperature of preheating/draw roll is set near the ceiling temperature that can stretch according to the fusing point and the crystallinity of the polypropylene-based resin that constitutes this substrate layer.As long as set as mentioned above, can make the MD stretched sheet of good high stretching ratio.

In addition, adopt coetrusion,, preferably in the polypropylene-based resin that constitutes substrate layer, add the resin that fusing point and crystallinity all are lower than this polypropylene-based resin in the situation of two sides lamination heat sealing layer.By operation like this, can improve stretchability, and can reduce MD preheat roll and draw roll temperature.Its result can prevent that heat sealing layer from adhering on the various MD rollers, and avoids stretching and hinder.

In addition, adopt coetrusion, situation at two sides lamination heat sealing layer, if with for example water below 40 ℃, the not stretched sheet that adopts coetrusion to be shaped is carried out water-cooled, then can reduce the temperature of setting MD preheat roll and draw roll significantly, make the MD stretched sheet of good high stretching ratio.This be because: because the sheet thing by chilling solidification of molten state, polyolefin resin that constitutes heat sealing layer and the polypropylene-based resin that constitutes substrate layer are solidified, so can reduce the temperature of setting MD preheat roll and draw roll under the state that crystalline growth is hindered.Its result can prevent that heat sealing layer from adhering on the various MD rollers, avoids stretching and hinders.

Biaxial stretch-formed lamination polypropylene resin film of the present invention, the tensile elongation of its MD need be for below 170%.In order to obtain this MD tensile elongation, be that high magnification more than 6 times stretches preferably by the stretching ratio of MD, simultaneously, as mentioned above the thickness of the heat sealing layer of substrate layer surface institute lamination is adjusted.

[lamination of Kaifeng band and Kaifeng band]

Film for packaging of the present invention, along the TD of the biaxial stretch-formed polypropylene resin film (comprising biaxial stretch-formed lamination polypropylene resin film) that constitutes it, lamination Kaifeng band.

For above-mentioned Kaifeng band, can use known Kaifeng band without restriction.Usually, will have not that stretching can be because of Kaifeng the time had both been ruptured and the film that extends this high tensile is processed into band shape.As above-mentioned film, can enumerate polyester film particularly and through uniaxial drawing or biaxial stretch-formed polyolefin film etc.

In addition, the face for lamination Kaifeng band has no particular limits, can be at biaxial stretch-formed polypropylene resin film arbitrary the lamination of (comprising biaxial stretch-formed lamination polypropylene resin film).For example, in the biaxial stretch-formed lamination polypropylene resin film, there is the situation of heat sealing layer on the two sides of substrate layer, can be at the surperficial lamination Kaifeng of arbitrary heat sealing layer band.In addition, only there is the situation of heat sealing layer in the one side of substrate layer, can be on the surface of substrate layer or the arbitrary surperficial lamination Kaifeng band on the surface of heat sealing layer.Also have, make the situation of packaging bag, though can be with in the inside of this packaging bag or arbitrary lamination Kaifeng of outside, if but at the outside of packaging bag lamination Kaifeng band, then see few waveform wrinkle that produces when crimping and thermal welding Kaifeng band sometimes easily, perhaps the slur that applies in the packaging bag outside is unclear.Therefore, preferred so that the Kaifeng band is positioned at this Kaifeng band of mode lamination of the inside of packaging bag.

In addition, according to packaged configuration of film for packaging etc., can suitably determine along the interval of the Kaifeng band of the TD lamination of film.Method as lamination Kaifeng band can adopt known method such as crimping method and hot melt connection.

In the film for packaging of the present invention, the end of the biaxial stretch-formed polypropylene resin film of Kaifeng band is arranged at lamination preferably, clip the Kaifeng band, grooving is set.

[processing of film for packaging, purposes (sandwich packaging bag)]

Film for packaging of the present invention carries out 2 processing (bag processing) by fusing sealing and/or heat seal, can be used for packing packaged body.Therefore, can be preferred for purposes such as sandwich packaging bag.Special situation about constituting by biaxial stretch-formed lamination polypropylene resin film at film for packaging of the present invention, so that become superimposed this film for packaging of mode of the inside of bag at least at the heat sealing layer of one lamination, utilize the fusing sealer, carry out bag, thus, can make packaging bag with extremely stable fusing sealing intensity.This be because: this heat sealing layer is made of low-melting polyolefin resin.Therefore, especially as the sandwich packaging bag, preferably use above-mentioned film for packaging.

Fig. 5 is the skeleton diagram of an example of the sandwich packaging bag of expression use biaxial stretch-formed polypropylene resin film of the present invention.In Fig. 5, along the TD of this film Kaifeng band N is set, in addition, grooving M is set in the end of the film of the Kaifeng mouth that is positioned at the Kaifeng band.

Embodiment

In order to specifically describe the present invention, enumerate following embodiment, but the present invention is not limited to these embodiment.At first, the measuring method that adopts is described in following embodiment.

(1) melt mass flow rate

Based on JIS-K7210, measure melt mass flow rate (below, slightly MFR).In addition, setting the mensuration temperature is 230 ℃ or 190 ℃.

(2) fusing point of resin

Utilize differential scanning calorimeter (Seiko electronics industry (strain) is made DSC6200R), under blanket of nitrogen, at 235 ℃, molten resin kept 10 minutes, then, with 10 ℃/minute cooling rate, was cooled to 30 ℃.Then,, be warming up to 235 ℃, in the endothermic curve that obtains, will show that the peak temperature of maximum heat absorption is as fusing point with 10 ℃/minute programming rate.

(3) copolymerization is formed

Utilize the nuclear magnetic resonance (NMR) light-dividing device (NEC's (strain) make JNM-GSX-270 ( ¹³C-nuclear resounce frequency 67.8MHz)), under following condition, measure copolymerization and form.

Mode determination: ¹The complete decoupling of H-

Pulse width: 90 degree pulses

Pulse recurrence time: 3 seconds

Integral number of times: 10000 times

Solvent: the component solvent of trichloro-benzenes/heavy benzol (76/24 capacity %)

Sample solution concentration: 120mg/2.5ml solvent

Measure temperature: 120 ℃

It is quantitative that copolymerization is formed: according to M.Kakugo, and Y.Naito, K.Mizunuma, T.Miyatake, [Macromolecules, 15,1150 (1982)] carry out the quantitative analysis that this copolymerization is formed.

(4) thickness of film

Utilize mechanical type thickness indicator ((strain) ミ ッ ト ョ makes micro-meter OMV-25DM), measure thickness (μ m).

(5) thickness of heat sealing layer

In liquid nitrogen, flooded biaxial stretch-formed lamination polypropylene resin film 30 minutes, it is freezed fracture.Utilize scanning electron microscope (NEC makes JSM-5600LV),, take the area of fracture of film, calculate the thickness (μ m) of heat sealing layer with multiplying power 5000.The film thickness of measuring according to the thickness of this heat sealing layer with in (4) is calculated the ratio of the gross thickness of heat sealing layer.

(6) transparency

Based on JIS-K7105, measure mist degree (mist value).

(7) pulling strengrth, tensile elongation

Cut the thin rectangular sample that 10mm is wide, 150mm is long respectively along MD, TD,,, measure pulling strengrth and tensile elongation respectively based on JIS-K7127 with 300mm/ minute draw speed.

(8) birefringence

Utilize automatic birefringence meter (prince's instrumentation machine (strain) is made KOBRA-21ADH), under following condition, measure birefringence.

Mensuration mode: parallel Nicol (Nicol) rotary process

Measure wavelength: 590nm

Phasic difference (Retardation) according to 0 ° of angle of incidence and 40 °, utilize the subsidiary software of this machine, calculate ratio of refraction (Nz) and the TD ratio of refraction in the face and poor (Ntd-Nmd) of MD ratio of refraction of the thickness direction of the interior TD ratio of refraction (Ntd) of face, the MD ratio of refraction (Nmd) in the face, film.As birefringence (Δ (δ) n), the absolute value of the TD ratio of refraction in the mensuration face at this moment and the difference of MD ratio of refraction (| Ntd-Nmd|).In addition, as the value of mean refractive index, input 1.490.

(9) tearing property evaluation: 45 tearing property of degree tests

Cut the film of the A4 version of MD shown in Figure 1, TD, utilize the heat seal machine, along the TD of this film L, the Kaifeng band K that thermal welding lamination 20mm is wide in the central, 165mm is long.

On film L, the position of the left and right sides 35mm at the center of being with K apart from breaking a seal, marking the length that being parallel to Kaifeng band K is datum line A, the A ' of 150mm.Secondly, on the top of Kaifeng band K the Kaifeng mouth B that 25mm is wide, 15mm is long is set.From the position that begins to tear of Kaifeng mouthful B is G, G '.Distance between datum line A and the datum line A ' is 70mm.In the TD of film direction, the end of directrix A ' A is identical with the position of G, G '.Then, use adhesive tape E, L is fixed on the ground paper J with this film.

As shown in Figure 2, tilt to be fixed in this sample on the ground paper J, and clamp with chuck C, the C ' of tensile machine.Along the direction of arrow, with 500mm/ minute the speed of tearing, mobile chuck C '.By aforesaid operations, the Kaifeng band application is added the power of 45 degree directions sideling, carry out tearing test.At this moment, top chuck C blocks this sample and ground paper, and bottom chuck C ' blocks the top of film and the Kaifeng band K of Kaifeng mouthful B.Here, datum line A that mark the position of the left and right sides, the center 35mm that is with apart from Kaifeng and the distance (70mm) between the datum line A ', in the sandwich corresponding to the open market sale, (the about 70mm) that the thickness of sandwich (width) is little.That is, consider that sandwich is scurried out easily in the situation of widening the Kaifeng part above this datum line.In addition, Fig. 3 is the lateral plan of the summary of expression sample when being fixed in chuck (not shown in the part of the Kaifeng of film superimposed layer band K and adhesive tape E etc.).

At Fig. 4, the sample behind the expression 45 degree tearing tests.One example of with dashed lines F, F ' expression tear portion.In addition, represent from beginning to tear position G, G ' arrival datum line A, the contact in A ' time with contact H.In addition, tear apart from I (mm) as 45 degree, with the distance of I among 4 following level evaluation Fig. 4.

Estimate ◎: 45 degree are torn distance for more than the 120mm.

Estimating zero: 45 degree, to tear distance above less than 120mm for 80mm.

Estimate △: it is above less than 80mm for 60mm that 45 degree are torn distance.

Estimate *: 45 degree are torn distance less than 60mm.

(10) antifog property

In the beaker of 100ml, add the water (18 ℃) of 50ml.Secondly, cover the rim of a cup of this beaker, make this no any wrinkle in film surface, fix, make sample with bungee with film.Then, in cold store (5 ℃), cooled off this sample 30 minutes, then,, estimate the state of the water droplet of (beaker inner face side) dewfall on the film surface according to 4 following ranks.

Estimate ◎: the water of dewfall is wetting on surface smoothing ground, and film is not fuzzy fully.

Estimate zero: the water of dewfall is formed big water droplet, and film is not fuzzy.

Estimate △: the water of dewfall is formed little water droplet, in the fuzzy part of existence everywhere of film.

Estimate *: the water of dewfall is formed ultrafine water droplet, and film becomes snow-white and equally blurs.

(11) fusing sealing intensity

Utilize fusing sealer (common prosperity (strain) is made the PP-500 type), the temperature of sealing sword be 380 ℃, bag speed be impact for 120 times/minute condition under, carry out bag.The fusing hermetic unit of the fusing sealing bag that makes is cut into the rectangular sample of weak point that 15mm is wide, 150mm is long.Then, utilizing tensile machine (Shimadzu Seisakusho Ltd. make AG500), is under 100mm/ minute the condition, this sample to be carried out tensile test at draw speed.Intensity during with the fracture of fusing hermetic unit is fusing sealing intensity (unit: N/15mm).

(12) heat-seal strength

Superimposed 2 rectangular samples of weak point wide with MD, that 150mm is long as the 15mm of length direction, the heat seal face is overlapped each other, utilize heat sealing machine (peace Tian Jingji (strain) makes the YSS type), in the temperature of upside metal fever seal bar is that 145 ℃, the temperature of downside polytetrafluoroethylene rubber are that 90 ℃, heat seal pressure are 0.1Mpa, heat seal time to be under 1 second the condition, carries out heat seal.Then, utilizing tensile machine (Shimadzu Seisakusho Ltd. make AG500), is under 100mm/ minute the condition, resulting heat seal sample to be carried out tensile test at draw speed.Maximum strength when heat sealing part is ruptured is as heat seal strength (unit: N/15mm).

Embodiment 1 (the not film of lamination heat sealing layer)

Under 245 ℃ extrusion temperature, by individual layer T mould, extrude Noblen (fusing point is that 161 ℃, MFR are that F301SPE/F301SPG, the mixture ratio that 3.2g/10 minute (230 ℃), プ ラ ィ system Port リ マ one make is 60: 40), make not stretched sheet.Utilize MD 2 stage stretcher, under 145 ℃, carried out for the 1st stage to stretch, this sheet material is stretched 5 times, again under 135 ℃, carried out for the 2nd stage to stretch, make all MD stretching ratios and be 7 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 186 ℃, draft temperature are 164 ℃),, this MD stretched sheet is stretched 11 times, make the biaxially-stretched film of the 30 μ m that do not implement corona treatment along TD.The fusing sealing intensity of the biaxially-stretched film that makes is 23.9N/15mm.Being evaluated as of antifog property *.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 2 (the not film of lamination heat sealing layer)

Under 245 ℃ extrusion temperature, by individual layer T mould, extrude Noblen (fusing point is that 161 ℃, MFR are that F301SPE/F301SPG, the mixture ratio that 3.2g/10 minute (230 ℃), プ ラ ィ system Port リ マ one make is 60/40), make not stretched sheet.Utilize MD 2 stage stretcher, under 142 ℃, carried out for the 1st stage to stretch, this sheet material is stretched 5.1 times, again under 138 ℃, carried out for the 2nd stage to stretch, make all MD stretching ratios and be 7.1 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 180 ℃, draft temperature are 162 ℃),, this MD stretched sheet is stretched 11 times, make the biaxial stretch-formed polypropylene resin film of the 25 μ m that do not implement corona treatment along TD.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 22.2N/15mm.Being evaluated as of antifog property *.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 3 (the not film of lamination heat sealing layer)

In embodiment 2, except that the biaxial stretch-formed polypropylene resin film of the 22 μ m that do not implemented corona treatment, carry out 2 identical operations with embodiment.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 20.3N/15mm.Being evaluated as of antifog property *.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Comparative example 1 (the not film of lamination heat sealing layer)

Under 230 ℃ extrusion temperature, by individual layer T mould, extrude Noblen (fusing point is that 161 ℃, MFR are that F201SPE/F201SPG, the mixture ratio that 2.2g/10 minute (230 ℃), プ ラ ィ system Port リ マ one make is 60/40), make not stretched sheet.Utilize MD 2 stage stretcher, under 143 ℃, carried out for the 1st stage to stretch, this sheet material is stretched 4.4 times, under 138 ℃, carried out for the 2nd stage to stretch, make all MD stretching ratios and be 4.6 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 184 ℃, draft temperature are 161 ℃),, this MD stretched sheet is stretched 10 times, make the biaxially-stretched film of the 30 μ m that do not implement corona treatment along TD.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 25.3N/15mm.Being evaluated as of antifog property *.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 4 (the not film of lamination heat sealing layer)

As substrate layer, adopt following method, making structure is 3 tunics on top layer/main stor(e)y/top layer.At first, as the raw material of main stor(e)y, mix the propylene-ethylene random copolymers (fusing point is that 156 ℃, ethylene contents are that 0.4 quality %, MFR are that 2.5g/10 minute (230 ℃), goods contain the antidim compound of 1.0 quality %, the resin 1 that サ Application ァ ロ マ one makes in the PC412Z table 2) of 75 quality % and the propylene-ethylene random copolymers of 25 quality % (fusing point is that 144 ℃, ethylene contents are that 2.5 quality %, MFR are the resin 2 in 2.0g/10 minute, Sumitomo Chemical manufacturing FH3315 table 2).Secondly, as the raw material on two top layers, (fusing point is 156 ℃ to mix the propylene-ethylene random copolymers of 75 quality %, ethylene contents is 0.4 quality %, MFR is 2.2g/10 minute (230 ℃), サ Application ァ ロ マ one makes PC412A), (fusing point is 144 ℃ to the propylene-ethylene random copolymers of 20 quality %, ethylene contents is 2.5 quality %, MFR is 2.0g/10 minute, Sumitomo Chemical is made the resin 2 in the FH3315 table 2) and the antiblocking agent masterbatch of 5 quality % (fusing point is 140 ℃, ethylene contents is 3.6 quality %, MFR is 8.0g/10 minute (230 ℃), the resin 7 that サ Application ァ ロ マ one makes in the PY630D table 2).Then, under 260 ℃ extrusion temperature, by 3 layers of T mould, the raw material on the raw material of the above-mentioned main stor(e)y of coextrusion and above-mentioned two top layers makes not stretched sheet.Follow again, utilize MD 2 stage stretcher, under 140 ℃, carried out for the 1st stage to stretch, with this not stretched sheet stretch 1.3 times, again under 146 ℃, carried out for the 2nd stage to stretch, make all MD stretching ratios and be 5.5 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 187 ℃, draft temperature are 152 ℃), along TD, this MD stretched sheet is stretched 10.3 times, then, implement corona treatment on the two sides, the thickness that so makes gross thickness and be 30 μ m, each top layer is that the thickness of 1.0 μ m, main stor(e)y is the biaxial stretch-formed polypropylene resin film of 28.0 μ m.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 18.2N/15mm, antifog property be evaluated as zero.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 5 (the not film of lamination heat sealing layer)

In embodiment 4, setting all MD stretching ratios is 6.0 times, and setting TD stretching ratio is 10.2 times, implement corona treatment on the two sides, the thickness that obtains gross thickness and be 30 μ m, each top layer is that the thickness of 1.0 μ m, main stor(e)y is the biaxial stretch-formed polypropylene resin film of 28.0 μ m, in addition, carry out 4 identical operations with embodiment.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 18.4N/15mm, antifog property be evaluated as ◎.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 6 (the not film of lamination heat sealing layer)

In embodiment 4, setting all MD stretching ratios is 6.5 times, and setting TD stretching ratio is 10.0 times, implement corona treatment on the two sides, the thickness that obtains gross thickness and be 30 μ m, each top layer is that the thickness of 1.0 μ m, main stor(e)y is the biaxial stretch-formed polypropylene resin film of 28.0 μ m, in addition, carry out 4 identical operations with embodiment.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 17.8N/15mm, antifog property be evaluated as ◎.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Comparative example 2 (the not film of lamination heat sealing layer)

In embodiment 4, setting all MD stretching ratios is 4.6 times, and setting TD stretching ratio is 9.3 times, implement corona treatment on the two sides, the thickness that obtains gross thickness and be 30 μ m, each top layer is that the thickness of 1.0 μ m, basic unit is the biaxial stretch-formed polypropylene resin film of 28.0 μ m, in addition, carry out 4 identical operations with embodiment.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 19.4N/15mm, antifog property be evaluated as ◎.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 7 (the not film of lamination heat sealing layer)

As substrate layer, adopt following method, making structure is 3 tunics on top layer/main stor(e)y/top layer.At first, as the raw material of main stor(e)y, mix the propylene-ethylene random copolymers (fusing point is that 156 ℃, ethylene contents are that 0.4 quality %, MFR are that 2.5g/10 minute (230 ℃), goods contain the antidim compound of 1.0 quality %, the resin 1 that サ Application ァ ロ マ one makes in the PC412Z table 2) of 25 quality % and the propylene-ethylene random copolymers of 75 quality % (fusing point is that 144 ℃, ethylene contents are that 2.5 quality %, MFR are the resin 2 in 2.0g/10 minute, Sumitomo Chemical manufacturing FH3315 table 2).Secondly, as the raw material on two top layers, (fusing point is 156 ℃ to mix the propylene-ethylene random copolymers of 25 quality %, ethylene contents is 0.4 quality %, MFR is 2.2g/10 minute (230 ℃), サ Application ァ ロ マ one makes PC412A), (fusing point is 144 ℃ to the propylene-ethylene random copolymers of 70 quality %, ethylene contents is 2.5 quality %, MFR is 2.0g/10 minute, Sumitomo Chemical is made the resin 2 in the FH3315 table 2) and the antiblocking agent masterbatch of 5 quality % (fusing point is 140 ℃, ethylene contents is 3.6 quality %, MFR is 8.0g/10 minute (230 ℃), the resin 7 that サ Application ァ ロ マ one makes in the PY630D table 2).Then, under 260 ℃ extrusion temperature, by 3 layers of T mould, the raw material on the raw material of the above-mentioned main stor(e)y of coextrusion and above-mentioned two top layers makes not stretched sheet.Follow again, utilize MD 2 stage stretcher, under 139 ℃, carried out for the 1st stage to stretch, with this not stretched sheet stretch 1.3 times, again under 144 ℃, carried out for the 2nd stage to stretch, make all MD stretching ratios and be 6.0 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 185 ℃, draft temperature are 150 ℃), along TD, this MD stretched sheet is stretched 9.5 times, implement corona treatment on the two sides, the thickness that makes gross thickness and be 30 μ m, each top layer is that the thickness of 1.0 μ m, main stor(e)y is the biaxial stretch-formed polypropylene resin film of 28.0 μ m.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 15.5N/15mm, being evaluated as of antifog property *.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 8 (the not film of lamination heat sealing layer)

In embodiment 7, setting all MD stretching ratios is 6.5 times, and setting TD stretching ratio is 9.3 times, implement corona treatment on the two sides, the thickness that obtains gross thickness and be 30 μ m, each top layer is that the thickness of 1.0 μ m, main stor(e)y is the biaxial stretch-formed polypropylene resin film of 28.0 μ m, in addition, carry out 7 identical operations with embodiment.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 15.3N/15mm, being evaluated as of antifog property *.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Embodiment 9 (the not film of lamination heat sealing layer)

In embodiment 7, setting all MD stretching ratios is 7.0 times, and setting TD stretching ratio is 9.2 times, implement corona treatment on the two sides, the thickness that obtains gross thickness and be 30 μ m, each top layer is that the thickness of 1.0 μ m, main stor(e)y is the biaxial stretch-formed polypropylene resin film of 28.0 μ m, in addition, carry out 7 identical operations with embodiment.The fusing sealing intensity of the biaxial stretch-formed polypropylene resin film that makes is 15.0N/15mm, being evaluated as of antifog property *.In table 1, the transparency, stretching ratio, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of the biaxial stretch-formed polypropylene resin film that expression makes.

Comparative example 3

Estimate fusing sealing intensity, the antifog property of the two sides antifog film commodity KF51#30 two sides corona treatment product of selling in market (サ Application ト ッ Network ス (strain) manufacturing) by name, its result, the fusing sealing intensity is 21.0N/15mm, antifog property be evaluated as ◎.In table 1, represent the transparency, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of this film.

Comparative example 4

General biaxial stretch-formed OPP film, the commodity PA20#30 one side by name corona treatment product (サ Application ト ッ Network ス (strain) manufacturing) that use market to sell, make the inside that is become bag by the face of corona treatment, make the fusing sealing bag, and mensuration fusing sealing intensity, its result, the fusing sealing intensity is 13.3N/15mm.In addition, also estimate the antifog property of corona treatment face.Its result, being evaluated as of antifog property *.In table 1, represent the transparency, the strength characteristics of mechanical aspects, birefringence, the evaluation of tearing property of this film.

Table 1

Project	Thickness (μ m)	Mist degree (%)	Stretching ratio (doubly)		Tensile elongation (%)		Pulling strengrth (MPa)		Birefringence (Δ N)	45 tearing property of degree
												MD	TD	MD	TD	MD	TD	|MD-TD|	Distance (mm)	Estimate
			Embodiment 1	30	3.3	7.0	11.0	118	56	215	291										0.00931	125	◎
Embodiment 2	25	2.6										7.1	11.0	117	62	211	298	0.00800	116	○
			Embodiment 3	22	2.5	7.1	11.0	116	63	213	290										0.00855	117	○
Comparative example 1	30	3.2										4.6	10.0	215	55	151	310	0.01681	47	×
			Embodiment 4	30	2.4	5.5	10.3	155	56	173	318										0.01368	96	○
Embodiment 5	30	2.4										6.0	10.2	141	61	191	324	0.01223	115	○
			Embodiment 6	30	2.5	6.5	10.0	129	62	200	314										0.01125	116	○
Comparative example 2	30	2.7										4.6	9.3	241	55	138	304	0.01588	21	×
			Embodiment 7	30	2.6	6.0	9.5	137	58	183	288										0.01077	148	◎
Embodiment 8	30	2.7										6.5	9.3	120	67	192	294	0.00956	146	◎
			Embodiment 9	30	2.6	7.0	9.2	106	65	205	290										0.00787	148	◎
Comparative example 3	30	2.7										-	-	232	46	152	281	0.01547	22	×
			Comparative example 4	30	3.2	-	-	210	49	140	335										0.01697	51	×

Embodiment 10 (film) with heat sealing layer

Adopt following method, make the biaxial stretch-formed lamination polypropylene resin film that it is configured to heat sealing layer/substrate layer (making substrate layer is 2 layers on main stor(e)y and top layer).At first, as the resin that constitutes heat sealing layer, prepare to be mixed with the compound (heat sealing layer resin) of the resin 7 shown in the table 2 of resin 5 shown in the table 2 of 95 quality % and 5 quality %.Secondly, as the raw material that constitutes substrate layer, preparation is mixed with the compound (main stor(e)y resin) of the resin 2 shown in the table 2 of resin 1 shown in the table 2 of 70 quality % and 30 quality %, and prepares to be mixed with the compound (top layer resin) of the resin 8 shown in the table 2 of resin 4 shown in the table 2 of 97 quality % and 3 quality %.This situation, relatively the object of fusing point is the resin 5 of heat sealing layer and the resin 1 of main stor(e)y.

Utilize extruder separately, according to the order of heat seal with resin/main stor(e)y resin/top layer resin, under 220～240 ℃ extrusion temperature, by 3 layers of T mould, above-mentioned each layer resin of coextrusion.Adopt the water-cooled casting method, cooling curing, the not stretched sheet of formation 3-tier architecture.Secondly, utilize MD 2 stage stretcher, under 135 ℃ preheating temperature, carry out the stretching of the 1st stage, this 3 synusia material is stretched 5.2 times, again under 122 ℃ preheating temperature, carrying out for the 2nd stage stretches, and makes all MD stretching ratios and be 6.8 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 186 ℃, draft temperature are 162 ℃), along TD, this MD stretched sheet is stretched 9.5 times, implement corona treatment on its two sides, the thickness that makes gross thickness and be 30 μ m, heat sealing layer is that the thickness of 1.5 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 28.5 μ m (thickness of main stor(e)y is that the thickness on 26.5 μ m, top layer is 2.0 μ m).

Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that maintenance so makes is after 2 days, measure its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tear the strength characteristics of directivity evaluation, mechanical aspects, in table 3, represent its result.In addition, in table 2, represent detailed composition, the fusing point of used resin.

Embodiment 11 (film) with heat sealing layer

Adopt following method, make its structure and be the biaxial stretch-formed lamination polypropylene resin film of heat sealing layer/substrate layer (making substrate layer is 2 layers on main stor(e)y and top layer).At first, as the resin that constitutes heat sealing layer, prepare to be mixed with the compound (heat seal resin) of the resin 7 shown in the table 2 of resin 5 shown in the table 2 of 95 quality % and 5 quality %.Secondly, as the raw material that constitutes substrate layer, preparation is mixed with the compound (main stor(e)y resin) of the resin 2 shown in the table 2 of resin 1 shown in the table 2 of 70 quality % and 30 quality %, and prepares to be mixed with the compound (top layer resin) of the resin 8 shown in the table 2 of resin 4 shown in the table 2 of 97 quality % and 3 quality %.This situation, relatively the resin of fusing point is resin 5 and resin 1.

Utilize extruder separately, according to the order of heat seal with resin/main stor(e)y resin/top layer resin, under 245～265 ℃ extrusion temperature, by 3 layers of T mould, above-mentioned each layer resin of coextrusion.Utilize chill roll, cooling curing, the not stretched sheet of formation 3-tier architecture.Secondly, utilize MD 2 stage stretcher, under 143 ℃ preheating temperature, carry out the stretching of the 1st stage, this 3 synusia material is stretched 1.2 times, again under 143 ℃ preheating temperature, carrying out for the 2nd stage stretches, and makes all MD stretching ratios and be 6.8 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 190 ℃, draft temperature are 155～164 ℃), along TD, this MD stretched sheet is stretched 9.0 times, implement corona treatment then on its two sides, the thickness that obtains gross thickness and be 30 μ m, heat sealing layer is that the thickness of 2.5 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 27.5 μ m (thickness of main stor(e)y is that the thickness on 25.5 μ m, top layer is 2.0 μ m).

Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that so makes of maintenance is after 2 days, measures its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 12 (film) with heat sealing layer

Adopt following method, make its structure and be the biaxial stretch-formed lamination polypropylene resin film of heat sealing layer/substrate layer (making substrate layer is 2 layers on main stor(e)y and top layer).At first, as the resin that constitutes heat sealing layer, prepare to be mixed with the compound (heat seal resin) of the resin 7 shown in the table 2 of resin 6 shown in the table 2 of 95 quality % and 5 quality %.Secondly,, prepare to be mixed with the compound (main stor(e)y resin) of the resin 2 of resin 3 shown in the table 2 of 70 quality % and 30 quality %, and prepare to be mixed with the compound (top layer resin) of the resin 8 of the resin 4 of 97 quality % and 3 quality % as the raw material that constitutes substrate layer.Relatively the resin of fusing point is resin 6 and resin 3.

Utilize extruder separately, according to the order of heat seal, under 220～240 ℃ extrusion temperature with resin/main stor(e)y resin/top layer resin, by 3 layers of T mould, above-mentioned each layer resin of coextrusion adopts the water-cooled casting method, cooling curing, the not stretched sheet of formation 3-tier architecture.Secondly, utilize MD 2 stage stretcher, under 135 ℃ preheating temperature, carry out the stretching of the 1st stage, this 3 synusia material is stretched 5.2 times, again under 122 ℃ preheating temperature, carrying out for the 2nd stage stretches, and makes all MD stretching ratios and be 6.8 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 186 ℃, draft temperature are 162 ℃), along TD, this MD stretched sheet is stretched 9.5 times, then, implement corona treatment on its two sides, the thickness that makes gross thickness and be 30 μ m, heat sealing layer is that the thickness of 1.5 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 28.5 μ m (thickness of main stor(e)y is that the thickness on 26.5 μ m, top layer is 2.0 μ m).

Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that maintenance so makes 2 days.Then, measure its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tear the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Comparative example 5 (film) with heat sealing layer

Adopt following method, making its structure is the biaxial stretch-formed lamination polypropylene resin film of heat sealing layer/substrate layer/heat sealing layer.At first, as the resin of the heat sealing layer that constitutes the two sides, prepare to be mixed with the compound (heat seal resin) of the resin 7 shown in the table 2 of resin 10 shown in the table 2 of resin 5, the 15 quality % shown in the table 2 of 80 quality % and 5 quality %.Secondly, as the raw material that constitutes substrate layer, prepare the resin 1 (main stor(e)y resin) shown in the table 2 of 100 quality %.Relatively the resin of fusing point is resin 5 and resin 10.

Utilize extruder separately, according to the order of heat seal resin/main stor(e)y resin/heat seal, under 240～260 ℃ extrusion temperature with resin, by 3 layers of T mould, above-mentioned each layer resin of coextrusion adopts the water-cooled casting method, cooling curing, the not stretched sheet of formation 3-tier architecture.Secondly, utilize MD 2 stage stretcher, again under 128 ℃ preheating temperature, carried out for the 1st stage to stretch, this 3 synusia material is stretched 1.1 times,, make all MD stretching ratios and be 4.6 times MD stretched sheet 128 ℃ of preheating temperatures of carrying out for the 2nd stage.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 186 ℃, draft temperature are 162 ℃), along TD, this MD stretched sheet is stretched 9.5 times, then, implement corona treatment on its two sides, the thickness that makes gross thickness and be 30 μ m, two heat sealing layers respectively is that the thickness of 1.5 μ m, base material film is the biaxial stretch-formed lamination polypropylene resin film of 27.0 μ m.

Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that maintenance so makes 2 days.Then, measure its fusing sealing intensity, heat seal strength, antifog property, the transparency, birefringence, tear the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result, in addition, in table 2, represent the detailed composition of used resin.

Embodiment 13 (film) with heat sealing layer

Adopt following method, making its structure is the biaxial stretch-formed lamination polypropylene resin film of heat sealing layer/substrate layer/heat sealing layer.At first, as the resin of the heat sealing layer that constitutes the two sides, prepare to be mixed with the compound (heat seal resin) of the resin 7 shown in the table 2 of resin 6 shown in the table 2 of 95 quality % and 5 quality %.Secondly, as the raw material that constitutes substrate layer, prepare to be mixed with the compound (main stor(e)y resin) of the resin 3 shown in the table 2 of resin 1 shown in the table 2 of 80 quality % and 20 quality %.Relatively the resin of fusing point is resin 6 and resin 1.

Utilize extruder separately, according to the order of heat seal resin/main stor(e)y resin/heat seal, under 200～240 ℃ extrusion temperature with resin, by 3 layers of T mould, above-mentioned each layer resin of coextrusion adopts the water-cooled casting method, cooling curing, the not stretched sheet of formation 3-tier architecture.Secondly, utilize MD 2 stage stretcher, under 122 ℃ preheating temperature, carry out the 1st stage MD and stretch, this 3 synusia material is stretched 5.2 times, again under 121 ℃ preheating temperature, carry out the stretching in the 2nd stage, make all MD stretching ratios and be 6.8 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 186 ℃, draft temperature are 166 ℃),, this MD stretched sheet is stretched after 10 times, implement corona treatment on its two sides along TD.The thickness that so makes gross thickness and be 30 μ m, two heat sealing layers respectively is that the thickness of 1.5 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 27.0 μ m.Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that so makes of maintenance is after 2 days, measures its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 14 (film) with heat sealing layer

Adopt following method, making its structure is the biaxial stretch-formed lamination polypropylene resin film of heat sealing layer/substrate layer/heat sealing layer.At first, as the resin of the heat sealing layer that constitutes the two sides, prepare to be mixed with the compound (heat seal resin) of the resin 7 shown in the table 2 of resin 6 shown in the table 2 of 95 quality % and 5 quality %.Secondly, as the raw material that constitutes substrate layer, prepare to be mixed with the compound (main stor(e)y resin) of the resin 3 shown in the table 2 of resin 1 shown in the table 2 of 80 quality % and 20 quality %.Relatively the resin of fusing point is resin 6 and resin 1.

Utilize extruder separately, according to the order of heat seal resin/main stor(e)y resin/heat seal, under 200～240 ℃ extrusion temperature with resin, by 3 layers of T mould, above-mentioned each layer resin of coextrusion adopts the water-cooled casting method, cooling curing, the not stretched sheet of formation 3-tier architecture.Secondly, utilize MD 2 stage stretcher, under 122 ℃ preheating temperature, carried out for the 1st stage to stretch, this 3 synusia material is stretched 5.2 times, under 121 ℃ preheating temperature, carried out for the 2nd stage to stretch, make all MD stretching ratios and be 6.8 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 183 ℃, draft temperature are 163 ℃),, this MD stretched sheet is stretched after 10 times, implement corona treatment on its two sides along TD.The thickness that so makes gross thickness and be 20 μ m, two heat sealing layers respectively is that the thickness of 1.5 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 17.0 μ m.Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that so makes of maintenance is after 2 days, measures its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Comparative example 6 (film) with heat sealing layer

Adopt following method, make its structure and be the biaxial stretch-formed lamination polypropylene resin film of heat sealing layer/substrate layer (making substrate layer is 2 layers on main stor(e)y and top layer).At first, as the resin that constitutes heat sealing layer, prepare to be mixed with the compound (heat seal resin) of the resin 7 shown in the table 2 of resin 5 shown in the table 2 of 95 quality % and 5 quality %.Secondly, as the raw material that constitutes substrate layer, preparation is mixed with the compound (main stor(e)y resin) of the resin 2 shown in the table 2 of resin 1 shown in the table 2 of 70 quality % and 30 quality %, and prepares to be mixed with the compound (top layer resin) of the resin 8 shown in the table 2 of resin 4 shown in the table 2 of 97 quality % and 3 quality %.Relatively the resin of fusing point is resin 5 and resin 1.

Utilize extruder separately, according to the order of heat seal with resin/main stor(e)y resin/top layer resin, under 245～265 ℃ extrusion temperature, by 3 layers of T mould, above-mentioned each layer resin of coextrusion utilizes chill roll, cooling curing, the not stretched sheet of formation 3-tier architecture.Secondly, utilize MD 2 stage stretcher, under 143 ℃ preheating temperature, carried out for the 1st stage to stretch, this 3 synusia material is stretched 1.2 times, under 143 ℃ preheating temperature, carried out for the 2nd stage to stretch, make all MD stretching ratios and be 5.2 times MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 190 ℃, draft temperature are 155～164 ℃),, this MD stretched sheet is stretched after 8.7 times, implement corona treatment on the two sides along TD.

The thickness that so makes gross thickness and be 30 μ m, heat sealing layer is that the thickness of 2.0 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 28.0 μ m (thickness of main stor(e)y is that the thickness on 26.5 μ m, top layer is 1.5 μ m).Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that so makes of maintenance is after 2 days, measures its fusing sealing intensity, heat seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 15 (film) with heat sealing layer

Improve the stretching ratio in the 2nd stage of MD 2 stage stretcher, setting all MD stretching ratios is 6.3 times, in addition, carry out and comparative example 6 identical operations, the thickness that makes gross thickness and be 30 μ m, heat sealing layer is that the thickness of 2.0 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 28.0 μ m (thickness of main stor(e)y is that the thickness on 26.5 μ m, top layer is 1.5 μ m).Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that so makes of maintenance is after 2 days, measures fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 16 (film) with heat sealing layer

Improve the stretching ratio in the 2nd stage of MD 2 stage stretcher, setting all MD stretching ratios is 6.8 times, stretch 9.0 times along TD, in addition, carry out and comparative example 6 identical operations, the thickness that makes gross thickness and be 30 μ m, heat sealing layer is that the thickness of 2.0 μ m, base material film is the biaxial stretch-formed lamination polypropylene resin film of 28.0 μ m (thickness of main stor(e)y is that the thickness on 26.5 μ m, top layer is 1.5 μ m).Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that maintenance so makes is after 2 days, measure its fusing sealing intensity, heat seal strength, antifog property, the transparency, birefringence, tear the strength characteristics of directivity evaluation, mechanical aspects, in table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 17 (film) with heat sealing layer

Improve the stretching ratio in the 2nd stage of MD 2 stage stretcher, setting all MD stretching ratios is 7.0 times, stretches 9.2 times along TD, in addition, carries out and comparative example 6 identical operations, makes biaxial stretch-formed lamination polypropylene resin film.Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that maintenance so makes is after 2 days, measure this its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tear the strength characteristics of directivity evaluation, mechanical aspects, in table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 18 (film) with heat sealing layer

The setting gross thickness is that the thickness of 30 μ m, heat sealing layer is that 5.0 μ m, substrate layer are 25.0 μ m (thickness of main stor(e)y is that the thickness on 23.5 μ m, top layer is 1.5 μ m), in addition, carry out 16 identical operations, make biaxial stretch-formed lamination polypropylene resin film with embodiment.Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that maintenance so makes is after 2 days, measure its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tear the strength characteristics of directivity evaluation, mechanical aspects, in table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 19 (film) with heat sealing layer

Adopt following method, make structure and be the biaxial stretch-formed lamination polypropylene resin film of heat sealing layer/substrate layer (making substrate layer is 2 layers on main stor(e)y and top layer).At first, as the resin that constitutes heat sealing layer, prepare to be mixed with the compound (heat seal resin) of the resin 7 shown in the table 2 of resin 9 shown in the table 2 of 95 quality % and 5 quality %.Secondly, as the raw material that constitutes substrate layer, preparation is mixed with the compound (main stor(e)y resin) of the resin 2 shown in the table 2 of resin 1 shown in the table 2 of 70 quality % and 30 quality %, and prepares to be mixed with the compound (top layer resin) of the resin 8 shown in the table 2 of resin 4 shown in the table 2 of 97 quality % and 3 quality %.Relatively the resin of fusing point is resin 9 and resin 1.

Then, utilize extruder separately, under 245～265 ℃ extrusion temperature, by 2 layers of T mould, coextrusion constitutes the main stor(e)y resin and the top layer resin of above-mentioned substrate layer.Utilize chill roll, cooling curing, the not stretched sheet of 2 layers of structure of formation.Secondly, utilize MD 2 stage stretcher, under 153 ℃ preheating temperature, carry out the stretching of the 1st stage, with these 2 layers not stretched sheet stretch 1.2 times, under 154 ℃ preheating temperature, carrying out for the 2nd stage stretches, and makes all MD stretching ratios and be 6.8 times and the MD stretched sheet that is made of substrate layer (making substrate layer is 2 layers on main stor(e)y and top layer).Then, utilize the online lamination machine that is provided with the individual layer mould in addition again, under 250 ℃,, extrude the also resin of lamination formation heat sealing layer on the main stor(e)y surface of this MD stretched sheet.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 190 ℃, draft temperature are 156～167 ℃),, have the MD stretched sheet of this heat sealing layer to stretch after 9.0 times lamination, implement corona treatment on its two sides along TD.

The thickness that so makes gross thickness and be 30 μ m, heat sealing layer is that the thickness of 2.0 μ m, substrate layer is the biaxial stretch-formed lamination polypropylene resin film of 28.0 μ m (thickness of main stor(e)y is that the thickness on 26.5 μ m, top layer is 1.5 μ m).Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that makes of maintenance is after 2 days, measures its fusing sealing intensity, heat seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 20 (film) with heat sealing layer

The thickness of setting gross thickness and be 32 μ m, heat sealing layer is that the thickness of the main stor(e)y of 4.0 μ m, substrate layer is that the thickness on 26.5 μ m, top layer is 1.5 μ m, in addition, carries out 19 identical operations with embodiment, makes biaxial stretch-formed lamination polypropylene resin film.Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that makes of maintenance is after 2 days, measures its fusing sealing intensity, heat seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 21 (film) with heat sealing layer

The thickness of setting gross thickness and be 37 μ m, heat sealing layer is that the thickness of the main stor(e)y of 9.0 μ m, substrate layer is that the thickness on 26.5 μ m, top layer is 1.5 μ m, in addition, carries out 19 identical operations with embodiment, makes biaxial stretch-formed lamination polypropylene resin film.Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that makes of maintenance is after 2 days, measures its fusing sealing intensity, heat-seal strength, antifog property, the transparency, birefringence, tears the strength characteristics of directivity evaluation, mechanical aspects.In table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Embodiment 22 (film) with heat sealing layer

Adopt following method, making its structure is the biaxial stretch-formed lamination polypropylene resin film of heat seal I layer/substrate layer (main stor(e)y)/heat-sealing II layer.At first,, prepare to be mixed with the compound of the resin 7 of the resin 9 of 95 quality % and 5 quality %,, prepare to be mixed with the compound of the resin 7 of the resin 6 of 95 quality % and 5 quality % as the resin that constitutes heat seal II layer as the resin that constitutes heat seal I layer.Secondly, as the raw material that constitutes substrate layer, prepare to be mixed with the compound (main stor(e)y resin) of the resin 2 of the resin 1 of 70 quality % and 30 quality %.Relatively the resin of fusing point is resin 9, resin 6 and resin 1.

Then, under 265 ℃ extrusion temperature,, extrude the main stor(e)y resin that constitutes above-mentioned substrate layer by individual layer T mould.Utilize chill roll, cooling curing makes the not stretched sheet of single layer structure.Secondly, utilize MD 2 stage stretcher, under 153 ℃ preheating temperature, carrying out for the 1st stage stretches, with this not stretched sheet stretch 1.2 times, under 154 ℃ preheating temperature, carry out the stretching of the 2nd stage, making all MD stretching ratios is 6.8 times and single layer MD stretched sheet.Then, utilize the online lamination machine that is provided with the individual layer mould in addition again, under 250 ℃, one side at this MD stretched sheet, extrude the resin that constitutes heat seal I layer, at MD stretched sheet lamination, at a superimposed layer heat seal I layer, obtain so MD stretched sheet, then, utilize the online lamination machine that the individual layer mould is set in addition again, under 250 ℃,, extrude the resin that constitutes heat-sealing II layer at the another side of this MD stretched sheet of lamination heat seal I layer not, and at this MD stretched sheet lamination, its structure is 3 layer laminate sheet materials of heat seal I layer/MD stretched sheet/heat-sealing II layer.Then, utilize the horizontal stretcher of stenter formula (preheating temperature is that 190 ℃, draft temperature are 156～167 ℃),, this 3 layer laminate sheet material is stretched after 9.0 times, implement corona treatment on its two sides along TD.

The thickness that so makes its gross thickness and be 34 μ m, heat seal I layer is that the thickness of 2.0 μ m, substrate layer is that the thickness of 28.0 μ m, heat seal II layer is the biaxial stretch-formed lamination polypropylene resin film of 4.0 μ m.Under 40 ℃, the biaxial stretch-formed lamination polypropylene resin film that maintenance makes is after 2 days, mensuration with heat seal I aspect as the transparency, the birefringence of the heat seal strength of the fusing sealing intensity in the bag, heat seal I aspect, the antifog property of heat seal I aspect, biaxial stretch-formed lamination polypropylene resin film, tear the strength characteristics of directivity evaluation, mechanical aspects, in table 3, represent its result.In addition, in table 2, represent the detailed composition of used resin.

Table 2

The resin numbering	The goods name	Detailed resin is formed
			Resin 1	PC412Z	Propylene-ethylene random copolymers fusing point is that 156 ℃, ethylene contents are that 0.4 quality %, MFR are 2.5g/10 minute (230 ℃), contain the antidim compound [manufacturing of サ Application ァ ロ マ one company] of 1.0 quality %
Resin 2	FH3315	Propylene-ethylene random copolymers fusing point is that 144 ℃, ethylene contents are that 2.5 quality %, MFR are (230 ℃) [sumitomo chemical company manufacturing] in 2.0g/10 minute
			Resin 3	F201SPK	The Noblen fusing point is that 160 ℃, MFR are 2.0g/10 minute (230 ℃), contain the antidim compound [manufacturing of プ ラ ィ system Port リ マ one company] of 1.0 quality %
Resin 4	F300SP	The Noblen fusing point is that 160 ℃, MFR are 3.0g/10 minute (230 ℃) [manufacturing of プ ラ ィ system Port リ マ one company]
			Resin 5	FS3611	Propylene-ethylene random copolymers fusing point is that 132 ℃, ethylene contents are that 5.1 quality %, MFR are (230 ℃) [sumitomo chemical company manufacturing] in 2.0g/10 minute
Resin 6	5C30F	Propylene-ethylene-1-butene terpolymers fusing point is that 130 ℃, ethylene contents are that 6.2 quality %, 1-butene content are that 5.1 quality %, MFR are 5.5g/10 minute (230 ℃) [manufacturing of サ Application ァ ロ マ one company]
			Resin 7	PY630D	The polypropylene type masterbatch fusing point of lubricant that contains decoupling agent (particulate that Polymer is spherical), the 10 quality % of 5 quality % is that 140 ℃ of MFR are 8.0g/10 minute [manufacturing of サ Application ァ ロ マ one company]
Resin 8	PY633B	Polypropylene type masterbatch, the fusing point that contains the decoupling agent (mineral-type particulate) of 4 quality % is that 140 ℃ of MFR are 8.0g/10 minute [manufacturing of サ Application ァ ロ マ one company]
			Resin 9	FV402	Straight chain shape low density polyethylene (LDPE) fusing point is that 117 ℃ of MFR are (190 ℃) [sumitomo chemical company manufacturing] in 4g/10 minute
Resin 10	XR110T	Propylene-butene-1 copolymer fusing point is that 110 ℃, 1-butene content are that 26 quality %, MFR are 6.0g/10 minute (230 ℃) [manufacturing of Mitsui Chemicals company]

Table 3

Project	Thickness	The ratio ※ 1 of the gross thickness of heat sealing layer	Mist degree	The fusing sealing intensity	Heat-seal strength	Antifog property	Stretching ratio		Tensile elongation		Pulling strengrth		Birefringence Ntd-Nmd	45 tearing property of degree
																μm	％	％	N/15mm	N/15mm	4 level evaluations	(doubly)		(％)		Mpa		ΔN	Distance	Estimate
	MD	TD	MD	TD	MD	TD		mm
										Embodiment 10	30	5.0	2.3	25.5	4.1							◎	6.8	9.5	130	63	210	280	0.00840	120	◎
Embodiment 11	30	8.3	3.5	28.6	5.7	◎	6.8	9.0	132							65	201	280	0.00823	111	○
										Embodiment 12	30	5.0	2.2	27.5	4.1							◎	6.8	9.5	124	60	204	299	0.00938	125	◎
Comparative example 5	30	10.0	2.7	21.4	4.2	◎	4.6	9.3	252							52	151	283	0.01549	22	×
										Embodiment 13	30	10.0	3.0	21.6	3.6							◎	6.8	10.0	144	59	195	272	0.00862	120	◎
Embodiment 14	20	15.0	2.3	20.0	3.6	◎	6.8	10.0	148							68	205	274	0.00759	115	○
										Comparative example 6	30	6.7	3.0	23.8	5.7							◎	5.2	8.7	207	53	128	261	0.01253	22	×
Embodiment 15	30	6.7	3.1	25.6	4.9	◎	6.3	8.7	164							50	185	243	0.00867	81	○
										Embodiment 16	30	6.7	2.6	25.3	4.6							◎	6.8	9.0	130	50	205	252	0.00801	149	◎
Embodiment 17	30	6.7	3.4	25.5	5.7	◎	7.0	9.2	124							48	217	259	0.00776	＞150	◎
										Embodiment 18	30	16.7	6.8	22.4	10.3							○	6.8	9.0	143	65	180	231	0.00778	121	◎
Embodiment 19	30	6.7	1.3	18.2	9.3	◎	6.8	9.0	142							64	166	260	0.00818	137	◎
										Embodiment 20	34	12.5	1.4	18.6	12.3							◎	6.8	9.0	150	72	159	263	0.00797	98	○
Embodiment 21	37	24.3	2.2	23.0	12.5	◎	6.8	9.0	147							69	166	226	0.00682	90	○
										Embodiment 22	34	17.6	3.0	18.7	9.4							◎	6.8	9.0	152	80	165	257	0.00809	＞150	◎

1: the gross thickness of heat sealing layer is with respect to the gross thickness of film

Claims (5)

1. film for packaging is characterized in that:

The tensile elongation of length direction is below 170%, constitute and constitute by having at least through the biaxial stretch-formed polypropylene resin film of biaxial stretch-formed substrate layer by polypropylene-based resin, and, the Kaifeng band is arranged along the Width lamination of this biaxial stretch-formed polypropylene resin film.

2. film for packaging as claimed in claim 1 is characterized in that:

The tensile elongation of the Width of described biaxial stretch-formed polypropylene resin film is 40～90%.

3. film for packaging as claimed in claim 1 or 2 is characterized in that:

Described biaxial stretch-formed polypropylene resin film is lower than the heat sealing layer that the polyolefin resin of this polypropylene-based resin constitutes being made of polypropylene-based resin and having by fusing point through at least one lamination of biaxial stretch-formed substrate layer.

4. film for packaging as claimed in claim 3 is characterized in that:

The gross thickness of described heat sealing layer be the biaxial stretch-formed polypropylene resin film thickness 0.8～25%.

5. one kind by the film formed sandwich packaging bag of each described packaging in the claim 1～4.

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