JPS63204252A - Cartridge container body for photographic film - Google Patents

Abstract

PURPOSE:To obtain a container body which has high drop strength in spite of a small thickness and has a small dimensional change of molding by forming said body of a specific PP resin. CONSTITUTION:This container body is formed of the PP resin contg. >=70wt.% either of a hompolypropylene resin having 16g/10min melt flow rate or propylene-alpha-olefin random copolymer resin contg. <=4.5wt.% alpha-olefin or the blended resins thereof, 3-20wt.% straight chain LDPE resin, 0.05-0.7wt.% fatty acid amide lubricant, and 0.01-0.5wt.% nucleating agent. The drop strength is thereby increased and the formation of the thin container body is permitted; in addition, the cost is reduced and the molding cycle is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a container body for accommodating a photographic film cartridge.

[Conventional technology]

In order to ensure rigidity and prevent fringing and stringing during injection molding, the conventional photographic film torone container body is
In order to ensure drop strength and minimize mold shrinkage changes, we use homopolypropylene resin with a melt flow rate (hereinafter referred to as MFR) of around 1011/10 minutes, and ethylene to improve drop strength and transparency while ensuring rigidity. A propylene/ethylene random copolymer resin containing about 1 weight percent of
No. 045, Japanese Utility Model Application Publication No. 163451/1983).

When a propylene/ethylene block copolymer resin is subjected to impact, it becomes white and has no commercial value, and its transparency is also very poor, so it was not put into practical use for long.

[Problem that the invention seeks to solve]

However, photographic film a using such resin
! ) The Rohne container body (hereinafter referred to as the container body) is made thick for various reasons such as ensuring drop strength and fluidity of molten resin during injection molding, so the amount of resin used can be reduced. The cost was often high. In addition, it is necessary to raise the resin temperature to ensure fluidity and molding balance, which not only increases the cooling time and increases molding costs, but also increases the molding shrinkage rate and changes the molding cycle in the same mold. was out of specification and required multiple molds. In addition, there was a problem in that the incidence of molding defects such as short shots, stringiness, and dirt residue υ during injection molding was high.

Furthermore, in the case of transparent containers, the mold core is finished with a mirror finish to prevent the transparency from decreasing due to the thick walls, so when the mold core is removed from the container body, the inside of the container body is momentarily in a vacuum state. The bottom and surrounding walls are prone to deformation (referred to as sinking and buckling) within and to the side of the container body.
Moreover, since a sharp explosion sound is generated when the mold core is pulled out of the container body, it is necessary to completely cool the mold core and slowly pull out the container body from the mold core, resulting in a long molding cycle.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a container body that has high drop strength even if it is thin and has small dimensional changes when molded.

[Means for solving problems]

The present invention has been made to achieve the above object, and the photographic film cartridge container body is made of homopolypropylene resin having a melt flow rate (ASTM test method D1238) of 16#/10 minutes or more, or a homopolypropylene resin containing α-olefin. 70% by weight or more of propylene-α-olefin random copolymer resin having a weight coefficient of 4.5% or less, or any of these blend resins, 3 to 20% by weight of linear low-density polyethylene resin, and a fatty acid amide-based lubricant. 'e0.05～
The main feature is that it is made of polypropylene resin containing 0.7% by weight and nucleating In-0.01 to 0.5% by weight.

The photographic film cartridge container film A/M of the present invention is made of a polypropylene resin, and the polypropylene resin is a homopolypropylene resin containing 70% by weight or more or an α-olefin content of 4.5% by weight or less. propylene-α-olefin random copolymer resin or a blend thereof. The propylene-α-olefin copolymer resin, which is the first component essential to the present invention, is required to have an α-olefin content of 4.5% by weight or less. α-olefin content is 4
．． If it exceeds 5% by weight, the rigidity becomes very low, sinking and buckling are likely to occur, and molding becomes difficult unless the container body is completely cooled and slowly removed from the mold core. Furthermore, even after being completely cooled, if it is stored in a silo or the like, it will deform, and molding failures such as stringiness and dirt residue will occur frequently. The α-olefin preferably has 2 to 10 carbon atoms, and ethylene is particularly preferred.

The linear low density polyethylene (hereinafter referred to as L-LDPE) resin, which is the second component essential to the present invention, consists of ethylene and an α-olefin having 4 to 10 carbon atoms, preferably 6 to 8 carbon atoms. It is a copolymer resin made by copolymerizing , and is a polyethylene resin with a linear straight chain structure with short branches.

L-LDPE resin improves drop strength more than expected without significantly reducing rigidity, transparency, surface strength, slipperiness, and moldability, promotes bleed-out of fatty acid amide-based lubricants, and changes molding cycle time. It is the only resin that can minimize dimensional changes even when exposed to heat. In order to use this L-LDPE resin to improve its drop strength, reduce molding costs and mold failure rates, and prevent sinking and buckling, it is necessary to use a specific type of polypropylene resin, fatty acid Specific amounts of amide lubricants and nucleating agents were required.

As the L-LDPE resin, commercially available products from various companies can be used, but 4-LDPE resin is particularly preferred, as it can greatly improve the drop strength and has fewer molding failures such as threads and dirt residue.
DPE resin has α-olefin -methylpentene-1
, hexene-1, or octene-1, MFR (ASTM
Test method D 1238) -1t15~20II/10
minute, density (ASTM test method D1505) is 0.91~
0.9351//cm" L-LDPE resin.

5 when the blend amount of L-LDPE resin is less than 3% by weight.
It is not possible to significantly improve the drop strength from 5 m, and when 20% by weight is applied, the drop strength from 5 m is greatly improved and the cracking rate becomes 0, but the compressive strength, transparency, and mating strength are decreases,
Stringing, dirt residue, sinking, buckling, and deformation occur frequently,
It is difficult to put it into practical use because it does not slide well and the container body may slide against each other, and it is difficult to take out the photographic film cartridge.

The fatty acid amide lubricant, which is the third component essential to the present invention, improves injection moldability, particularly the fluidity of the resin and the mold releasability from the mold core. In addition, since a thin film of fatty acid amide is formed on the surface of the container body using its bleed-out property, it prevents the surface from being scratched and slippery, preventing the container bodies from blocking each other, and improving transportability. improve.

Furthermore, the inner surface of the container body is made slippery to prevent it from buckling when it sinks into the bottom, making it easier to take out the photographic film cartridge. If the amount added is less than 0.055% by weight, the above-mentioned improvement effect will be small, and there will be problems in resin compositions in which the drop strength is completely improved. If the amount added exceeds 0.7% by weight, it will be difficult to blend into the resin, and screw slip will occur, reducing the injection amount. Not only does the surface of the molded container body become sticky and give a bad feel, but also dirt and dust tend to adhere to it, and the transparency decreases.

Representative commercial product names of fatty acid amide lubricants particularly preferred for the present invention are listed below, but the present invention is not limited thereto.

Oleic acid amide lubricants: Armosuri, ZoCP (Lion Akzo Co., Ltd. product), Neutron (Nippon Toka Co., Ltd. product), Neutron-P [Nippon Tokko Co., Ltd. product],
Amide O (Nitto Chemical Co., Ltd. product), Alflo EIO
(Nippon Oil & Fats Co., Ltd. product), Diamond 0-200 (
Erucic acid amide lubricants such as Nippon Kasei Co., Ltd. product), Diamond G-200 (Nippon Kasei Co., Ltd. product); Alflow P-10 (Nippon Oil & Fats Co., Ltd. product), Neutron-8 (E1 Honseika (Nippon Kasei Co., Ltd. product) stearyl erucic acid, such as Alflo S-10 (product of NOF Corporation), Neutron 2 (product of Nippon Toka Co., Ltd.), Diamond 200 (product of Nippon Kasei Co., Ltd.), etc. Amide lubricants; SNT (product of Hiki Seika Co., Ltd.), etc. Bis-fatty acid amide lubricants; Bisamide (product of Nippon Kasei Co., Ltd.), Diamond 200 Bis (product of Nippon Kasei Co., Ltd.), Armowa, Kusu EBS (Lion)・Behenic acid amide lubricant such as Akzo Co., Ltd. product): BNT (Nippon Toka Co., Ltd.)
products) etc.

Fatty acid amide lubricants may be used alone or in combination of two or more types, or may be used in combination with other lubricants.

In either case, the fatty acid amide lubricant may be contained in the polypropylene resin composition in an amount of 0.05 to 0.7 weight percent.

The nucleating agent, which is the fourth component essential to the present invention, increases the rigidity of the resin composition and increases the crystallization temperature, thereby preventing bottom sinkage and buckling even if the cooling time is shortened, and making it possible to prevent the occurrence of bottom sink and buckling immediately after molding. This has the effect of making it difficult to deform even when a large amount is placed in a container or container.

Furthermore, since it is possible to greatly improve transparency, it is particularly effective for transparent container bodies. Polypropylene resin alone greatly reduces drop strength because it promotes crystallization, but a polypropylene resin composition blended with L-LDPE resin completely covers this drawback and can be applied to concrete floors from 1 < 5 m. This prevents cracks from occurring even if the camera is dropped from the bottom corner with a photographic film cartridge inserted. Organic as a nucleating agent,
Although it is possible to use various known inorganic materials,
Representative examples of particularly preferred organic nucleating agents that exhibit the above-mentioned effects without adversely affecting the photographic film are described below, but it goes without saying that the present invention is not limited thereto.

1・3, 2・4. Diynecylidene sorbitol: The chemical structural formula is CH-0-H H-0-CH \□, in which 2 moles of benzaldehyde are bonded to 1 mole of sorbitol. Even if the Hensen ring in the above chemical structural formula has a substituent such as methyl, ethyl, bff1y, lauryl, stearyl, etc., the same effect can be obtained.

Sorbitol is a hexahydric alcohol that has a very wide range of uses as a sugar alcohol, and is obtained by dehydrating benzaldehyde in the presence of an acid catalyst.

The chemical structural formula of this derivative, which has a particularly large transparency effect, is shown below.

1. Other high-purity alkyl-substituted dipendylidenesorpitol, etc., and 1, 3.2, and 4. produced by condensation reaction of 2 moles of trialdehyde and 1 mole of sorbitol. Di(methylbenzylidene)
These include sorbitol and di-substituted benzylidene sorbitol compounds represented by the following formulas, such as 1,3,2,4-bis(methylbenzylidene) sorbitol and 1,3,2,4-bis(ethylbenzylidene) sorbitol. In addition, there are products in which the surface of 1, 3, 2, and 4° dibenzylidene sorbitol is coated with a blunt material of higher fatty acids.

If the amount added is less than 0.0-1 weight ratio, it will have little effect and will only increase blending costs, and if it exceeds 0.5 weight ratio, there will be no increase in the amount and the cost will increase. Depending on the type of nucleating agent, it may have an adverse effect on photographic film or significantly reduce its drop strength. Nucleating agents can be used alone or in combination of two or more. Further, an organic nucleating agent and an inorganic nucleating agent may be used together.

Methods for blending the nucleating agent into the polypropylene resin composition of the present invention include the tri-blend method and the master patch method, but since the bulk specific gravity is 0.1 ± 0.02 and the bulk is high and it is easy to scatter, It is difficult to blend it, so it is best to mix it with a small amount of dispersant or wetting agent. Examples of effective dispersants include caldic anhydride and higher fatty acids, and lubricants such as oleic acid amide, which is another essential component of the present invention, are particularly preferred.

Plasticizers such as DOP and DHP can be used as wetting agents.

1.3.2.4. Adding dibenzylidene sorbitol or its derivatives using the master patch method at several times to several tens of times the concentration used in the α-olefin/propylene random copolymer resin prevents scattering, provides good dispersion even in low-temperature molding, and is suitable for other additions. can be completely dispersed and mixed with the agent,
It is preferable because it is easy to add and inexpensive.

Pure products of higher fatty acids 1, 3, 2, 4. It is also preferable to coat or blend the surface of dibenzylidene sorbitol or its derivatives to enhance the dispersion effect and prevent bleeding.

The polypropylene resin described above preferably has a melt flow rate of 8 #/10 minutes or more. Also,
Additives such as various pigments, metal powders, antioxidants, and various thermoplastic resins can be blended with the polypropylene resin as necessary. These additives include (
There are some listed in the Glass Data Handbook published by Kogyo Research Association Co., Ltd. For example, it is preferable to add 0.01 to 0.2% by weight of a phenolic antioxidant. The inventor of the present invention has discovered that unless the antioxidant or oxide is kept at a weight ratio of 0.2 or less, it will have an adverse effect on the photographic film (density unevenness, fogging and changes in sensitivity will occur).

The shape of the container body of the present invention is not particularly limited as long as it can accommodate the film t+)o-ne, but it must be able to sufficiently fit and seal with the container carrier and the container cap can be attached and detached. For example, the lids shown in FIGS. 1 to 3 are preferred, and the lids shown in FIGS. 1 and 2 have the advantage of being easy to open with one hand.

In FIG. 1, the reference numeral 1 is a photographic film No. 9 Torone container body, and the reference numeral 2 is a photographic film No. 9 Torrone container carrier. The container body 1 has a cylindrical shape with a bottom, and the opening edge of the peripheral wall 3 is formed to be thick and swells inward, and has a circular cross section into which the lip 8 of the container cap 2 fits into the inner peripheral surface. An arcuate groove 4 is formed. In addition, the center of the bottom part 5 should be moved inward by about 0.5 to 5 cm, preferably about 1 to 3 fi, from the surface of the bottom part 5 so that the resin injection port mark 7 left behind protruding into the resin injection part 6 does not protrude from the bottom part 5. It is formed by a depression.

The container body 1 shown in FIG. 2 is different from the container body 1 shown in FIG.
is the same as

In the container body 1 shown in FIG. 3, a lip 9 having an arcuate cross section is formed on the outer side of the upper end of the peripheral wall 3, and this lip 9 fits into a groove 10 of the container cap 2.

Ru.

Generally, the Film Noctrone container is commercialized by being stored in a paper box as an outer box together with the Film Noctrone instruction manual, but since the container body of the present invention is also characterized by transparency, By using the outer box, it is possible to further demonstrate its characteristics and reduce costs. Examples of container bodies for such uses are shown in FIGS. 4-6. Figure 4 shows cylindrical shape, Figure 5 shows 4
FIG. 6 shows an example in which the outer shape is four corners and the storage portion is circular.

Additionally, if the bottom part 5 is insufficiently cooled during injection molding, when the mold core is pulled out from the container body, the space between the container body and the mold core will be in a vacuum state, and the bottom part and the surrounding wall will dent inward (bottom (sinking and buckling). In order to prevent this sinking and buckling, as shown in FIG.
It is formed to bulge out by about 2 gourds, and the space between the bottom part 5 and the peripheral wall part 3 is formed in a relatively large arc shape, and the inner peripheral surface of the peripheral wall part 3 is formed to be inclined outward by 0.01 to 2 m. Preferably. Furthermore, a mold core 11 with unevenness formed on the surface
to form irregularities on the inner circumferential surface of the peripheral wall portion 3, and
It is preferable to prevent air from entering through the gap between the mold core 11 and the mold core 11 to create a vacuum state. The depth of this unevenness is 1μ~
It may be a plurality of 0.4 m parallel pieces, a combination of vertical and horizontal lines, a satin finish, a silk texture, a lattice pattern, etc., and the bottom may also have an uneven surface. Improves sink sink prevention effect.

There are various injection molding methods. For example, the efficiency of using a combination of two methods such as injection-blow molding, the most common injection molding method, vacuum injection molding within a credit mold, and multi-stage molds such as stack mold (21 cotton mold). Uses traditional injection molding. The material of the container character f2 is preferably one that is more flexible than the container main body 1 in order to allow the container main body 1 to sufficiently exhibit the above-mentioned functions. A polyethylene resin containing 0.05 to 0.6 weight percent is suitable.

[Effect]

The photographic film cassette container body of the present invention has polypropylene resin that increases rigidity, and L-LD.
PE resin increases drop strength etc.

Furthermore, the fatty acid amide lubricant improves the fluidity of the resin and the mold releasability from the mold core, and the nucleating agent increases rigidity and crystallinity, making it difficult to deform.

〔Example〕

Inventive products ■ and ■, conventional products I and ■, and comparative products I~
The experimental results comparing the characteristics of (2) will be explained.

Inventive product (■) is a propylene-ethylene random copolymer resin with an ethylene content of 2.0% by weight, and a melt flow rate (MFR) (AST Test Method Riichi 1238) of 3.
7 g/10 min, flexural modulus (ASTM test method D-790
) is 11.400 kg/cm2. Izotsu impact value (
ASTM test method D-256) is 6.5 kg-cm/c
m, haze (ASTM test method D-1003) is 16.7
L-LDPE resin is made by copolymerizing 84.5% by weight of the related resin and 4-methylpentene-1, and has a MFR (ASTM
Test method Riichi 1238) is 8. P/10 min, density (AST
A polypropylene resin containing 15% by weight of a resin with M test method D-1505) of 0.920.9/α3, 0.3% by weight of a fatty acid amide lubricant, and 0.2% by weight of a nucleating agent was used. .

Inventive product (2) is a propylene-ethylene random copolymer resin with an ethylene content of 2.3% by weight and an MFR of 36.
#/10 minutes, flexural modulus is 9,900 ky/cm2,
L-LDPE resin is made by copolymerizing 89.5% by weight of a resin with an Izod impact value of 6.9 kl/-cm/l:m and a haze of 16.1, and 4-methylpentene-1.
A polypropylene resin with an FR of 8y/10 min, a density of 0.920 g/F3, 10% by weight of a resin, a fatty acid amide lubricant of 0.3% by weight, and a nucleating agent of 0.2% by weight was used. .

Conventional product I has an MFR of 9. F/10 minutes, flexural modulus is 1
8.000 kg/cm”, Izod impact value 2k
a-cm/cm and only homopolypropylene resin with a haze of 73.3% was used.

Conventional product ■ is a propylene-ethylene random copolymer resin with an ethylene content of 1.5% by weight, and an MFR of 15#.
/10 minutes, flexural modulus is 11,200 soft ν, Izod impact value is 3 ky-cm/α, and haze is 56.7.
% resin was used.

Comparative product ■ is a propylene-ethylene random copolymer resin with an ethylene content of 2.0% by weight and an MFR of 35F.
/10 minutes, 99.7% by weight of resin with flexural modulus of 9,700 kg/cm2, Izod impact value of 3.8 kg-cm/cm, and haze of 64.5, and 0 fatty acid amide lubricant. .3% by weight of resin was used.

Comparative product (■) is a resin containing 99.5% by weight of the same zolopyrene-ethylene random copolymer resin as inventive product I, 0.3% by weight of fatty acid amide lubricant, and 0.2% by weight of nucleating agent. was used.

Comparative product ■ is a propylene-ethylene random copolymer resin with an ethylene content of 2.3% by weight and an MFR of 35.
g/l 0 minutes, bending modulus 9,000 kg/cm2
, 99.7% by weight of a resin having an Izot impact value of 4.3 kg-cm/cm and a haze of 65.11, and a resin containing 0.3% by weight of a fatty acid amide lubricant were used.

Comparative product (2) is the same as the invention product (2) except that 99.5% by weight of progylene-ethylene random copolymer resin was used instead of L-LDPE resin.

The molding machine used was Nestal (trade name) manufactured by Sumitomo Heavy Industries, the mold pressure was 150 tons, the number of molds was 24, the runner type was a hot runner, and the shape was as shown in Figure 1, with an average side wall thickness of 0.7 m. The cartridge main body was molded.

The molds used for the conventional and comparative products had a mirror-finished mold core surface.

The mold of the present invention is manufactured by first polishing the surface of the mold core in the horizontal direction (parallel to the bottom), and then polishing it vertically (in the direction of removing the mold core from the container body, perpendicular to the bottom) for two to 30 minutes as final polishing. 5μ
Parallel streak-like unevenness was left in the vertical direction at a depth of m.

The experimental results are shown in Table 1.

The evaluation in the table is based on the following.

◎Very good ○ Excellent △　Practical limit M: Some problems (needs improvement) × Not practical The tests in the table are as follows.

*1 Rate of cracking when dropped from a height of 5m; Rate of cracking when dropped from a height of 5m onto a concrete floor after putting 36 shots of photographic film (Fujicolor HR-10036EX) in a cartridge and sealing with a cap. environmental temperature 10℃).

*2 Occurrence of deformation (bottom sinkage, buckling): Attach vermilion to the bottom of the container body, press it on a blank sheet of paper like a stamp, and visually observe the pressed shape.Buckling is measured and evaluated by roundness (however, when cooled (compared assuming the same time).

*3 Dimensional variation: Measure and compare the inner diameters of container bodies molded with the same cooling time.

Large working dimension fluctuations (molding yield) It was determined that the shrinkage rate) was low.

*4 Transparency: line thickness 0.5 m + gap 2III+
Transparency is defined as the distance (cm) where the parallel lines on the transparency test sheet on the back of the container body become invisible when the container body is placed between the transparency test sheet and the eye on which parallel lines of + are drawn on a blank sheet of paper and moved away from the eye. do.

FIG. 8 is a graph showing the temperature dependence of falling weight impact strength. In this test, a test piece with a thickness of 1.5 fi was formed using the resin used for the invention product (1), comparative product (2), and conventional product (2), and each test piece was subjected to a drop weight impact test using the ASTM D-1709 test method. The strength was measured.

From the results of this experiment, the resin used in the invention product (■) has a higher falling weight impact value than the comparative product (■) and the resin of the conventional product I in all temperature ranges, and in particular, the falling weight impact value is significantly superior even in the low temperature range. ing.

〔Effect of the invention〕

Photographic film of the present invention t4) The Rohnay container body has high drop strength and good fluidity of the resin, so it can be formed thin and costs can be reduced. Furthermore, since deformation is less likely to occur, the cooling time can be shortened and the molding cycle can be shortened. Furthermore, with the same cooling time, the dimensional variation is very small, and the allowable range of molding cycle variation has been greatly expanded, so even if the molding cycle is changed, the dimensions of the container body remain within the standard, and there is no need to modify the mold. Ta. It also has higher transparency.

[Brief explanation of the drawing]

The drawings all represent embodiments of the present invention, and FIGS. 1, 2, and 3 are cross-sectional views of the container body and the container cap. 4 to 6 are perspective views of an example container body that can also be used as an outer box, and FIG. 7 is a partial sectional view of the container body in which irregularities are formed on the peripheral wall. FIG. 8 is a diagram showing the temperature dependence of falling weight impact strength. 1... Photographic film A? ) Rhone container body, 2...
・Photographic film arm trone container kiya, 7', 3...
Peripheral wall part, 4...Groove, 5...Bottom part, 11...Mold core. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] Homopolypropylene resin with a melt flow rate of 16 g/10 minutes or more, or an α-olefin content of 4.5
Up to 70% by weight of propylene-α-olefin random copolymer resin or any of these blend resins
3 to 20% by weight or more of linear low-density polyethylene resin
Weight%, fatty acid amide lubricant 0.05-0.7% by weight
A photographic film cartridge container body, characterized in that it is formed of a polypropylene resin containing 0.01 to 0.5% by weight of a nucleating agent.