JPH09165482A - Composition for sheet for back cover of file and sheet for back cover of file - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet compsn. for a back cover of a file which has excellent strength, oleic acid resistance and other properties by mixing a particular propylene/ethylene random copolymer, a hydrogenated diene copolymer, and a nucleating agent together in predetermined proportions. SOLUTION: A propylene/ethylene random copolymer (A), having a melt flow rate (230 deg.C, load 2.16kg) of 0.5 to 30g/10min, an ethylene content of 0.5 to 5wt.%, and a quantity of heat of melting of 60 to 120J/g as measured by differential scanning calorimetry, in an amt. of 80 to 97wt.%, 20 to 3wt.% hydrogenated diene copolymer (B), and a nucleating agent (C) (e.g. (1,3)2,4- dibenzylidene sorbitol) in an amt. of 0.05 to 0.5 pts.wt. based on 100 pts.wt. in total of the components (A) and (B) are mixed together to prepare a composition for a sheet for a back cover of a file. The component (B) is pref. a copolymer having a refractive index of 1.48 to 1.5 and a modulus of elasticity of 30 to 200kgf/cm<2> . Specific examples thereof include a hydrogenated styrene/1,3- butadiene copolymer and a hydrogenated styrene/isoprene copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent file backstrip sheet composition and a file backstrip sheet which are attached for the purpose of sandwiching a piece of paper on which heading information, reference numbers, etc. are inserted so that they can be replaced. .

[0002]

2. Description of the Related Art FIG. 1 is a perspective view of an example of a file to which a spine cover sheet for inserting a piece of paper in which a file information heading or the like is inserted is attached. Conventionally, such a file has a file base material (2) as shown in FIG.
The back cover sheet (3) is heat-sealed and bonded to both ends (FIG. 2 (a)), and then bent and formed into a predetermined shape (FIG. 2 (b)). File base material (2)
As a material, a thin paper sheet (221) and a polypropylene skin material (22) thermally laminated with transparent random propylene (222) are bonded to a thick paper base material (21) using glue and water. Etc. are used (FIG. 3).

The back cover sheet (3) which is heat-sealed to the polypropylene skin (22) of the file base material (2) has conventionally been transparent, flexible and non-glossy and has an appropriate tensile strength. A polyvinyl chloride-based resin sheet is widely used in which physical properties such as can be easily controlled by adding a plasticizer or the like.

However, the polyvinyl chloride resin has environmental problems such as generation of odor during processing and molding, residual odor of products, generation of toxic gas during waste incineration and residual metal components. It has a drawback that additives such as plasticizers and stabilizers, which are blended in a large amount, bleed to deteriorate surface characteristics (feeling) and transparency. In addition, since the back cover sheet is repeatedly touched by hand, there is a problem that the sheet material is deformed or deteriorated (discolored) by the action of the oleic acid component contained in the secretion from the skin.

Therefore, the present invention has no environmental problems, has the physical properties such as transparency, flexibility, proper luster and tensile strength required for a file back cover, and does not deform or deteriorate for a long period of time.
An object of the present invention is to provide a file composition for a file backstrip and a file backstrip sheet having resistance to deterioration due to skin secretion (oleic acid).

[0006]

[Means for Solving the Problems] The inventors of the present invention are keen to use a polypropylene-based resin, which has no environmental problems, as a base resin of a sheet composition for a file back cover, in place of a conventional polyvinyl chloride-based resin. Repeated research. As a result, a composition containing a propylene-ethylene random copolymer having specific physical properties, a hydrogenated diene-based copolymer, and a nucleating agent in specific amounts was used, and a molded sheet was provided with a flow direction (M
The inventors have found that the above problems can be solved by adjusting the heat shrinkage ratios in D) and the width direction (TD) to fall within specific ranges, and have completed the present invention.

That is, the present invention provides a sheet composition for a file spine cover and a sheet for a file spine cover having the following constitution. (1) (a) Melt flow rate (230 ℃, 2.16kg
Load) 0.5 to 30 g / 10 minutes, ethylene content 0.5 to 5.0
% By weight, heat of fusion determined from differential scanning calorimetry (Δ
Hm) 60 to 120 J / g propylene-ethylene random copolymer 80% by weight to 97% by weight, (b) hydrogenated diene copolymer 3 to 20% by weight, and the components (a) and (b). The total amount of 100 parts by weight of (c) the nucleating agent is 0.
05-0.5 parts by weight of a sheet composition for spine covers. (2) The refractive index of the hydrogenated diene-based copolymer of the component (b) is
1. The composition according to 1 above, which has a modulus of 1.48 to 1.50 and an elastic modulus of 30 to 200 kgf / cm ² . (3) Forming the composition according to 1 or 2 into a sheet,
A sheet for a back cover, which is formed by adjusting the heat shrinkage ratios in the machine direction (MD) and the width direction (TD) of the formed sheet to 0.2 to 0.9%.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. [File composition component for back cover sheet] (a) Propylene-ethylene random copolymer The propylene-ethylene random copolymer used in the present invention means propylene and ethylene in the presence of a stereoregular polymerization catalyst such as a Ziegler system. Is a crystalline propylene-ethylene copolymer obtained by random copolymerization of and with an ethylene content of 0.5 to 5.0% by weight, preferably 2.0 to 4.0% by weight, and a melt flow rate (MFR) (JIS K7210,230).
℃, 2.16kg load) 0.5 to 30g / 10 minutes, preferably
1.0 to 20 g / 10 minutes, and has a heat of fusion (ΔHm) of 60 to 120 J / g, preferably 90 to 1 determined by differential scanning calorimetry (DSC) defined below.
20 J / g.

When the ethylene content exceeds 5.0% by weight,
As the crystallinity decreases, the rigidity decreases greatly, the heat resistance is impaired, and the secondary workability when the molded sheet is bonded to the file body decreases. On the other hand, the ethylene content is 0.
If it is less than 5% by weight, the sheet moldability and adhesiveness are deteriorated and the molding shrinkage is increased, such being undesirable. MFR is 0.5 g / 1
If it is less than 0 minutes, the sheet formability is deteriorated, and 30 g / 10
If the amount is exceeded, sheet forming becomes difficult.

In the present specification, "the amount of heat of fusion (ΔHm) determined from the differential scanning calorimetry" means that the resin sample is 2
When the heat of fusion is measured by a differential scanning calorimeter while heating to 00 ° C., the peak between 85 and 175 ° C. is defined as the melting peak, and the calorific value of the melting peak is divided by the sample weight (g). When the ΔHm of the propylene-ethylene random copolymer used in the present invention is less than 60 J / g, the transparency of the obtained sheet decreases, and when it exceeds 120 J / g, the heat shrinkage rate increases and the secondary workability deteriorates. To do.

(B) Hydrogenated Diene Copolymer The hydrogenated diene copolymer used in the present invention is a polymer block (A) mainly containing a vinyl aromatic compound and a conjugated diene polymer or (A)-(B) or (A)-comprising a conjugated diene-vinyl aromatic compound random copolymer block (B) mainly containing a conjugated diene.
(B)-(A) block copolymer, or a taper block (C) which further comprises a vinyl aromatic compound and a conjugated diene and in which the vinyl aromatic compound component gradually increases along the molecular chain.
In the block copolymer (A)-(B)-(C) consisting of and, the double bond residue of the conjugated diene moiety is hydrogenated and saturated. The hydrogenation rate is at least 80%, preferably 90% or more of the double bond residue.

The polymer block (A) is a block containing a vinyl aromatic compound in an amount of 80% by weight or more, preferably 90% by weight or more, and a conjugated diene or the like as another monomer component. The polymer block (B) contains the conjugated diene compound in an amount of 80% by weight or more, and the conjugated diene portion has a vinyl bond (1,2-bond) bonding amount of 25% or more. Further, the vinyl aromatic compound component is preferably 10 to 30% by weight in the whole block copolymer.

Specific examples of the vinyl aromatic compound include styrene, t-butylstyrene, α-methylstyrene and p.
-Methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene, vinylpyridine and the like are mentioned, and styrene and α-methylstyrene are preferable. Further, as the conjugated diene, for example, 1,3-butadiene, isoprene, 2,
3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, chloroprene and the like, 1,3-Butadiene, isoprene and 1,3-pentadiene are preferred.

The hydrogenated diene copolymer used in the present invention is
Its number average molecular weight is 50,000 to 600,000, MFR (230 ° C,
2.16 kg load) is 3 to 6 g / 10 minutes, and it is particularly preferable that the refractive index is 1.48 to 1.50 and the elastic modulus is 30 to 200 kgf / cm ² . When the refractive index is out of the above range, the component (a)
And the transparency of the propylene-ethylene random copolymer becomes large. If the elastic modulus is out of the above range, good flexibility and touch cannot be obtained.

(C) Nucleating Agent In the present invention, an organic phosphoric acid-based, carboxylic acid-based or sorbitol-based nucleating agent is used as the nucleating agent. The transparency of the sheet is improved by using the nucleating agent. As the organic phosphoric acid-based nucleating agent, an ammonium salt of an organic phosphoric acid ester, an organic ammonium salt or a metal salt (for example, sodium bis (4-t-butylphenyl) phosphate,
Sodium-2,2'-methylenebis (4,6-di-t
-Butylphenyl) phosphate etc.),
Examples of the carboxylic acid type nucleating agent include an aluminum salt or sodium salt of an aromatic carboxylic acid, and examples of the sorbitol type nucleating agent include a dibenzylidene sorbitol compound.

Of these, sorbitol-based nucleating agents are preferable, and specifically, (1,3) 2,4-dibenzylidene sorbitol, (1,3) 2,4-di (p-methylbenzylidene) sorbitol, (1,3) 2,4-di (p-
Ethylbenzylidene) sorbitol, (1,3) 2,4
-Di (p-chlorobenzylidene) sorbitol, (1,
3) 2,4-di (p-methoxybenzylidene) sorbitol is preferred.

In the transparent sheet of the present invention, an ultraviolet stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent (including a surfactant), a color pigment, a flame retardant, and Other additives such as a foaming agent, silicone oil, and an inorganic filler can be appropriately added as needed.

[Blending Ratio of Each Component] In the present invention, the blending ratio of the resin component is 80 to 97% by weight of the propylene-ethylene random copolymer (a) and 20% of the hydrogenated diene copolymer (b). ˜3% by weight, preferably 9% of component (a)
0 to 97% by weight, and the component (b) is 10 to 3% by weight.
When the ratio of the component (a) is less than 80% by weight, tensile strength and olefin acid resistance, which is an index of deterioration resistance due to skin secretion, are lowered, and blocking during molding tends to occur.
Further, since the component (b) is expensive, it is disadvantageous in terms of production cost. On the other hand, when the proportion of the component (a) exceeds 97% by weight, the effect of the blending of the component (b) does not appear, the flexibility is lowered, and the tactile sensation is deteriorated. The content of the nucleating agent (c) is 0.05 to 0, based on 100 parts by weight of the total of the components (a) and (b).
5 parts by weight. If the amount of the component (c) added is less than 0.05 parts by weight, the transparency is poor, and if it exceeds 0.5 parts by weight, the effect is leveled off and the production cost is disadvantageous.

[Sheet Composition for File Back Cover and Method for Producing Sheet] The sheet composition for a file back cover of the present invention comprises the above composition components (a), (b), (c) and other additives. It can be manufactured by the method conventionally used for manufacturing sheets and films.
For example, a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneading roll, a Brabender, a mixture of the above components.
After melt-kneading with a kneader such as a kneader ruder, a sheet is formed with an extruder or the like. As for the sheet thickness
It is preferably about 0.1 to 0.5 mm.

The obtained sheet has a length of 10 cm in the machine direction (MD) of the molded sheet and a length of 5 c in the width direction (TD).
It is necessary that the thermal contraction rate calculated by holding a sheet sample with a thickness of 1.5 mm and a thickness of 1.5 mm for 40 hours at 65 ° C. and measuring the lengths before and after that is in the range of 0.2 to 0.9%. Is. If the heat shrinkage exceeds 0.9%, the shrinkage becomes large during heat sealing when adhering to the spine of the file, and the secondary workability deteriorates. On the other hand, if the heat shrinkage is less than 0.2%, it is not preferable because it causes slack in the sheet portion when the sheet is used as a file back cover sheet. Heat shrinkage (0.2
.About.0.9%) for the molded sheet in an air bath at a temperature 5 to 10 ° C. lower than the heat distortion temperature, that is, 30 to 60 ° C., preferably 35 to 55 ° C., for 30 minutes to 72 hours, preferably 12 It can be performed by heating for 48 hours and then gradually cooling. If necessary, the sheet may be fixed using a jig to prevent deformation, and the sheet may be treated in a water bath or a salt bath to prevent discoloration due to oxidation in an air bath.

The transparent sheet obtained as described above is heat-bonded to the spine of the file and used as a sheet for the spine of the file. Adhesion to the back cover of the file is performed by heat-sealing the both ends of the back cover sheet (3) to the file base material (2) at a temperature of about 170 to 190 ° C by the method described in the section of the prior art. Done.

[0022]

The present invention will be specifically described below with reference to examples and comparative examples. The following raw materials and additives were used in Examples and Comparative Examples.

(A) Propylene-ethylene random copolymer (RPP) (a-1) RPP-1, ethylene content 3% by weight, MFR
(230 ℃, 2.16kg load) 9g / 10min, heat of fusion (Δ
Hm) 92 J / g; (a-2) RPP-2, ethylene content 3% by weight, MFR
(230 ℃, 2.16kg load) 9g / 10min, heat of fusion (Δ
Hm) 115 J / g; (a-3) RPP-3, ethylene content 3% by weight, MFR
(230 ° C, 2.16 kg load) 1.7 g / 10 minutes, heat of fusion (ΔHm) 93 J / g; (a-4) RPP-4, ethylene content 3% by weight, MFR
(230 ° C., 2.16 kg load) 1.3 g / 10 minutes, heat of fusion (ΔHm) 90 J / g; (a-5) RPP-5, ethylene content 3% by weight, MFR
(230 ° C, 2.16 kg load) 0.3 g / 10 minutes, heat of fusion (ΔHm) 90 J / g; (a-6) RPP-6, ethylene content 3% by weight, MFR
(230 ° C, 2.16 kg load) 1.3 g / 10 minutes, heat of fusion (ΔHm) 55 J / g.

(B) Hydrogenated diene copolymer Dynaron 1320P (manufactured by Japan Synthetic Rubber Co., Ltd.), bound styrene content 10%, Shore A hardness 39, MFR (230
℃, 2.16kg load) 3.5g / 10min, hydrogenation rate 99% or more, refractive index 1.49, elastic modulus 40kgf / cm ² .

(C) Nucleating agent (1,3) 2,4-di (p-methylbenzylidene) sorbitol (Gelol MD (manufactured by Shin Nippon Rika Co., Ltd.)).

(D) Homopolypropylene (PP) MFR (230 ° C., 2.16 kg load) 9 g / 10 minutes.

(E) Polyvinyl chloride (PVC) A soft transparent sheet for stationery (made by Shin-Etsu Chemical Co., Ltd.) having an elastic modulus of 2000 kgf / cm ² and a thickness of 0.15 mm.

Examples 1 to 6, Comparative Examples 1 to 6 Each component was added and blended in the proportions shown in Tables 1 and 2, and dry blended using a super mixer, and then a 50 mmφ extruder (L / D = 28, kneading Pellets were formed using a temperature of 250 ° C., and the pellets were molded into a sheet having a thickness of 0.15 mm, followed by heat treatment at 40 ° C. for 30 hours. The heat shrinkage, 1% tensile modulus, transparency, olefin acid resistance (appearance and shrinkage), heat deterioration resistance, moldability, and touch of the obtained sheet were measured and evaluated. The results are shown in Tables 1-2.

The physical properties shown in Tables 1 and 2 were measured and evaluated by the following methods. -Heat shrinkage (MD, TD): Flow direction of molded sheet (M
D) Length 10 cm, width direction (TD) length 5 cm, thickness 0.
A 15 mm sheet sample was kept at 65 ° C. for 40 hours, and calculated from the ratio of the length before treatment to the length before treatment (minus (−) sign indicates expansion). 1% tensile modulus: measured according to JIS K7127. -Transparency: Measured according to JIS K7105.

Olefinic acid resistance: Appearance: A sheet sample having the same shape as that used for the above heat shrinkage measurement was dipped in oleic acid and kept at 23 ° C. for 24 hours, and then the appearance was visually evaluated. ◯: Film surface is good. Δ: The film surface is slightly blistered and the smoothness is deteriorated. X: A large amount of swelling occurs on the film surface, and smoothness and transparency decrease. -Shrinkage rate (MD, TD): A sheet sample having an MD length of 10 cm, a TD length of 5 cm, and a thickness of 0.15 mm is dipped in oleic acid and treated at 23 ° C. for 24 hours, and the length after dipping to the length before dipping It was calculated from the ratio of the heights (minus (-) sign indicates expansion).

Heat resistance deterioration resistance: A sheet sample having an MD length of 10 cm, a TD length of 5 cm and a thickness of 0.15 mm was placed in an oven, heated to 100 ° C., the appearance was observed, and the number of days until yellowing was measured.

Moldability: The rolled sheet at the time of forming the sheet was evaluated as "O" when it did not block and had good moldability, and "X" when it caused blocking and was inferior in moldability.

Feeling: A sensory test was conducted by panelists (10 people). The organoleptic test was based on the transparent sheet of polyvinyl chloride resin used in Comparative Example 6, with viscoelastic properties and smoothness as the functional factors, those with the same or higher grade were marked with "○", and those with poor grade were marked with "×". Was evaluated as follows. A: O is 90% or more. B: O is 30% or more and less than 90%. C: ○ is less than 30%.

[0034]

[Table 1]

[0035]

[Table 2]

As is clear from Tables 1 and 2, the sheet made of only the propylene-ethylene random copolymer (Comparative Example 1) has good transparency but poor flexibility, and thus has poor tactile sensation. The resulting sheet (Comparative Example 2) has good oleic acid resistance, but is inferior in flexibility as in the case of the propylene-ethylene random copolymer, and thus has poor tactile sensation and a large shrinkage ratio. When a propylene-ethylene random copolymer having a small MFR is used (Comparative Example 3), blocking occurs at the time of winding the sheet, resulting in poor moldability, and if the blended amount of the hydrogenated diene copolymer is too large. (Comparative Example 4) Oleic acid resistance and moldability are deteriorated, and when a small ΔHm is used (Comparative Example 5), oleic acid resistance and transparency are deteriorated, which is not preferable.
Further, the conventional transparent sheet made of polyvinyl chloride (Comparative Example 6) is easily deteriorated by heat, is inferior in tensile strength, and is insufficient in oleic acid resistance.

On the other hand, the transparent sheet of the present invention (Examples 1 to 6) prepared by blending a propylene-ethylene random copolymer having specific physical properties, a hydrogenated diene copolymer and a nucleating agent in specific amounts. ) Has little heat shrinkage and is excellent in all physical properties such as tensile strength, oleic acid resistance, heat deterioration resistance, transparency, moldability, and tactile sensation, and shows good physical properties as a file back cover sheet composition. .

[0038]

EFFECT OF THE INVENTION A sheet comprising the sheet composition for a file spine of the present invention comprises a propylene-ethylene random copolymer having specific physical properties, a hydrogenated diene copolymer and a specific amount of a nucleating agent. And tensile strength, oleic acid resistance, heat deterioration resistance, transparency, and moldability required for a file spine sheet by specifying heat shrinkage in the machine direction (MD) and width direction (TD) of the formed sheet. Also, it has excellent physical properties in both touch and touch, and has no environmental problems as compared with conventional sheets using polyvinyl chloride.

[Brief description of the drawings]

FIG. 1 is a perspective view of an example file.

FIG. 2 is a file cross-sectional view showing a step of adhering a back cover sheet.

FIG. 3 is a cross-sectional view showing a configuration of a back cover sheet base material.

[Explanation of symbols]

 1 ... file, 2 ... file base material, 3 ... spine cover sheet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C08L 47:00)

Claims (3)

[Claims] 1. A melt flow rate (230 ° C.,
2.16kg load) 0.5-30g / 10min, ethylene content 0.5
-5.0 wt%, propylene-ethylene random copolymer having a heat of fusion (ΔHm) 60-120 J / g determined by differential scanning calorimetry 80-97 wt%, (b) hydrogenated diene-based copolymer 3- 20% by weight, and 0.05 to 0.5 parts by weight of the nucleating agent (c) per 100 parts by weight of the components (a) and (b) in total, and a sheet composition for a back cover. 2. The composition according to claim 1, wherein the hydrogenated diene copolymer as the component (b) has a refractive index of 1.48 to 1.50 and an elastic modulus of 30 to 200 kgf / cm ² . 3. The composition according to claim 1 or 2 is formed into a sheet, and the heat shrinkage in the machine direction (MD) and the width direction (TD) of the formed sheet is adjusted to 0.2 to 0.9%. File for back cover sheet.