JPH02264941A - Resin for molding spool of photographic film cartridge and manufacture of the same - Google Patents

Abstract

PURPOSE:To obtain the resin for molding the spool of the photographic film cartridge small in stains due to a metallic mold with good producibility by dispersing bis-fatty acid amide into the kneaded mixture of a general-purpose polystyrene resin and an impact-resistant polystyrene resin. CONSTITUTION:The resin for molding the spool to be used is obtained by dispersing the bis-fatty acid amide into the kneaded mixture of the general-purpose polystyrene resin and the impact-resistant polystyrene resin, thus permitting the obtained molding resin to allow the bis-fatty acid amide to act as a releasing agent at the time of molding with the metallic mold, and not to deposit a fatty acid on the mold due to its low volatility and the absence of any free fatty acid, and accordingly, to reduce mold stains, and the 2 kinds of polystyrenes to be well mixed by mixing the bis-fatty acid amide with the mixture of the polystyrenes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel molding resin for a spool of a photographic film cartridge and a method for manufacturing the same.

[Conventional technology]

Polystyrene resin is used as the base resin for spools for photographic film cartridges due to its appearance, molding dimensional stability, strength, and heat resistance. Generally, impact-resistant polystyrene resin (hereinafter sometimes referred to as old PS) is made by graft polymerizing synthetic rubber such as butadiene rubber to styrene monomer.
A blend of general purpose polystyrene resin (hereinafter also referred to as GPPS) is used.

When composed only of GPPS, due to the hard and brittle physical properties of the resin, the spool may be damaged due to protrusion during mold release, damage may occur during automatic transport to the film winding process, and the user may accidentally use the film. GPPS alone is not suitable as a spool resin because it is easily damaged when dropped. On the other hand, using only HIPS is more expensive than GPPS and poses a cost problem.

For this reason, a mixture of GPPS and old PS is used as the base resin.

The mixing ratio of GPPS and old PS is not particularly specified, as it varies depending on the use of the photographic spool and the physical properties of each resin, especially the amount of rubber, quality, particle size, etc. of old PS.

Since a photographic spool is loaded with a photosensitive film that is subject to fogging due to light, it naturally requires light-shielding properties, and for this purpose carbon black powder is added. Also 2
In order to reduce the increase in film pull-out resistance due to frictional resistance with various parts of the cartridge provided on the outside of the spool, there is a technique to knead a lubricant into the molded resin, as described in Utility Model Publication No. 81-3000. This is especially effective when kneading silicone into resin.

JP-A-83-318553 describes a method for manufacturing a molded resin for a spool of a photographic film cartridge. The polystyrene resin used in this method can be obtained by continuous bulk polymerization, suspension polymerization, etc. Polystyrene in suspension polymerization.

Due to the process, it is obtained in the form of particles with a diameter of 0.2 to 1 mm. Particulate GPPS and old PS are mixed by putting GPPS and old PS at a predetermined ratio into a mixer such as a Henschel mixer, and stirring the mixture. At this time, metal salts of higher fatty acids are added to ensure uniform mixing. Zinc stearate is often used as the metal salt of higher fatty acids because it also serves as a mold release agent when molding the kneaded resin.

[Problem to be solved by the invention]

However, when a styrene resin containing a metal salt of a higher fatty acid is molded, there is a drawback that the higher fatty acid adheres to the mold, transfers to the molded product, or corrodes the mold.

In many cases, mold deposits are a mixture of so-called sweating components and higher fatty acids resulting from thermal decomposition of metal salts of higher fatty acids. The sweating component is liquid paraffin contained in the resin and components in the low molecular weight range of the resin that are decomposed by heating and liquefied on the surface of the mold. Therefore,
Mold deposits give the appearance of a liquid. The sweating component evaporates in a few hours at room temperature, so when mold deposits are transferred and adhered to the molded product, higher fatty acids gradually precipitate from the initial liquid and remain in the form of a stain.

The mold deposits that have transferred to the photographic film spool separate from the spool during the film winding process, contaminate the winding machine, and eventually transfer to the photographic film again, causing the product to lose its functionality. A problem arises. In order to prevent this, if the surface of the mold is frequently cleaned to prevent mold deposits from adhering to the molded product, a problem arises in that productivity decreases.

An object of the present invention is to provide a molding resin for a spool of a photographic film cartridge and a method for manufacturing the same, which improves the problems of the prior art described above.

[Means to solve the problem]

According to the present invention, the above object can be achieved by a molding resin for a spool of a secondary photographic film cartridge and a method for manufacturing the same.

■ A molded resin for spools of photographic film cartridges, which is characterized by having bis-fatty acid amide dispersed in a mixture of general-use polystyrene resin and impact-resistant polystyrene resin.

■ A molding resin for the spool of a photographic film cartridge characterized by mixing general-use polystyrene resin particles and impact-resistant polystyrene resin particles with bis-fatty acid amide and melt-kneading to obtain a polystyrene resin kneaded product in which bis-fatty acid amide is dispersed. Production method.

[Effect]

Bis fatty acid amide in the molding resin for spools.

It acts as a mold release agent during molding, and is less volatile than metal salts of higher fatty acids when heated. This is because bis fatty acid amides have only covalent bonds and no ionic bonds, and are structurally different from metal salts of higher fatty acids, and also because they do not have free fatty acids. Therefore, most of what adheres to the mold is the sweating component, which evaporates and reduces staining.

Furthermore, when mixing the general-use polystyrene resin particles and the impact-resistant polystyrene resin particles, the bis fatty acid amide reduces the friction of the particles, so that they can be mixed well.

[Preferred embodiment]

The molding resin for a spool of the present invention contains carbon black powder, and preferably further contains a silicone compound.

In the method for producing a molded resin for a spool according to the present invention, carbon black powder and a silicone compound can be added.

The bis fatty acid amide preferably has a melting point of 140° C. or higher, and specifically includes N-N'-ethylene bis stearamide. This structure is shown below.

CH-NHCO-C17H35 CH-NHCOφC17H35 Bis fatty acid amide is added in an amount within a range that reduces friction of the particles and allows good mixing when mixing general polystyrene resin particles and impact-resistant polystyrene resin particles. Preferably, it is added in an amount of 0.03 to 0.1% by weight based on the total weight of the molding resin. If it is less than 0.03% by weight, the effect may not be clear, and if it exceeds 0.1% by weight, the screws of the mixer and molding machine may slip during the kneading and molding processes after mixing. . Bis fatty acid amide is 1. For example, 200 mesh particles are 9
Those containing 0% or more can be mixed.

The impact-resistant polystyrene resin is made of one or more rubbers such as conjugated 1.3 diene polymers such as butadiene, isoprene, and chlorobrene, styrene-butadiene copolymer rubber, 2-butyl rubber, etc., and styrenic monomers. It is a resin obtained by graft polymerization of polystyrene resin, and is a polystyrene resin that has higher impact resistance than general polystyrene resin. General-purpose polystyrene resin is a polystyrene resin obtained by polymerizing styrene monomers.

Carbon black powder is added to ensure light-shielding properties. The amount of carbon black powder added is determined by the thickness of the thinnest part of each part of the spool.
Light-shielding properties are ensured at 1 to 1% by weight. In a spool for regular 35mm photographic film, 0.2 to 1% by weight.
added. Preferred carbon black powders have an average particle diameter of 15 to 120 mu, from the viewpoint of light blocking properties and no adverse effects on photographic films (occurrence of fogging, decrease in sensitivity, adhesion, etc.).
An oil furnace carbon black powder having a pH of 6 to 8 is more preferable than a pH of 5 to 9.

The carbon black powder can preferably be added as a master patch pellet. The master patch pellets can be added, for example, when mixing GPPS particles and 128 particles with bis fatty acid amide. As the base resin for the master patch pellet, 2, for example old PS or GPPS, can be used alone, or a mixture thereof can also be used.

As the general-use polystyrene resin particles, particles obtained by suspension polymerization or the like can be used.

The particle size of these particles is, for example, about 0.2 to IIL11.

As the impact-resistant polystyrene resin particles, particles obtained by graft polymerization or the like can be used, and the particle size of these particles is, for example, about 0.2 to 1.5 mm.

When these particles are mixed with the bis fatty acid amide, a device such as a Henschel mixer can be used. The obtained mixture is melt-kneaded using, for example, a single-screw or twin-screw kneader to obtain a kneaded polystyrene resin in which bis fatty acid amide is dispersed. This mixer can be obtained as a pellet. For example, the diameter or side is 2 to 5
IDI can be made into spherical and cylindrical pellets.

When dispersing carbon black powder into the mixed material,
Preferably, this is carried out by mixing and dispersing master patch pellets containing carbon black powder into the mixture. in this case.

Higher fatty acid metal salts such as zinc stearate may be added to better disperse the carbon black powder, but in order to prevent it from adhering to the mold, it should not exceed 0.05% by weight (based on the total weight of the molding resin). (preferably 0.03% by weight or less)
Make it.

The molding resin of the present invention can also contain a silicone compound in order to reduce the resistance force for drawing out the film due to frictional resistance with each part of the cartridge. The silicone compound also acts as a mold release agent. Preferably, it is contained in an amount of 0.5 to 2% by weight based on the total weight of the molding resin. A preferred silicone compound is a silicone oil having a dimethylsiloxane structure. Its structure is as follows.

(n is an integer of 1 or more) The silicone compound can be added, for example, directly to a polystyrene resin (including both general and impact resistant) mixed materials in which bisamide fatty acid amide is dispersed, and It can also be added in a predetermined amount as a master patch pellet containing a high concentration in advance. Alternatively, the addition can be carried out and dispersed simultaneously with the dispersion of carbon black powder (preferably in the form of master patch pellets).

It can also be added and dispersed after the carbon black powder is dispersed.

In the molding resin of the present invention, general polystyrene resin (
GPPS) and impact-resistant polystyrene resin (IIIPs)
Although the content can be changed depending on the physical properties of the impact-resistant polystyrene resin, - for boat fishing, 5% by weight or more of old PS is included.

Additionally, various additives may be appropriately blended into the molding resin of the present invention, if necessary. For example, antioxidants, light stabilizers, ultraviolet absorbers, nucleating agents, antistatic agents, dispersants, lubricants,
These include neutralizing agents, acid scavengers, and inorganic fillers. For example, when carbon black powder or a silicone compound is made into a master patch pellet and dispersed in a polystyrene resin, these additives can be added to the master patch pellet and dispersed in the polystyrene resin.

〔Example〕

Example 1 General-purpose polystyrene resin particles (particle size 0.2 to 1 mm) and impact-resistant polystyrene resin particles (particle size 0.2 to 1 mm) obtained by suspension polymerization were mixed with ethylene bis at a ratio of 7:3. Stearamide (Alflo H-50, manufactured by NOF Corporation) was added and mixed, and melt mixing was performed using a twin-screw extruder to obtain polystyrene resin pellets in which ethylene bisstearamide was dispersed. A carbon black-containing master patch pellet and a silicone-containing master patch pellet obtained separately were mixed with this polystyrene resin pellet and melt-kneaded to obtain a molded resin of the present invention. This molding resin contains 0.1% by weight of ethylene bisstearamide and 0.5% by weight of carbon black powder.

Dispersed were 0.031ff1% zinc stearate and 1.5% by weight silicone compound. Note that the zinc stearate is 1. It is added to disperse carbon black powder well.

Example 2 A molded resin of the present invention was obtained in substantially the same manner as in Example 1 above. This molding resin contains 0.05% ethylene bisstearamide and 0.05% carbon black powder.
5% by weight, 0.03% by weight of zinc stearate and 1.5% by weight of silicone compound.

Example 3 A molded resin of the present invention was obtained in substantially the same manner as in Example 1 above. This molding resin contains 0% ethylene bisstearamide, 051i ffi%, and 0% carbon black powder.
．． 5% by weight, 0.05% by weight of lead stearate? 6 and 1.5% by weight of silicone compound were dispersed.

Comparative Example In Example 1 above, a molded resin was obtained by adding zinc stearate instead of ethylene bisstearamide.

This molding resin contains 0.5% by weight of carbon black powder.
, 0.08% by weight of zinc stearate and 1.5% by weight of a silicone compound were dispersed therein.

(Comparative Experiment) The molded resins of Examples 1 to 3 and Comparative Example were molded using a photographic film spool mold. During molding, 1000 molded products were checked every 2 hours for the presence or absence of mold deposits transferred to the molded products. When the number of molded products to which mold deposits were transferred reached 5 (0.5%), molding was stopped and the mold was cleaned. Table 1 shows a summary of the time from the start of molding to the stop of molding for each of the molding resins.

Since the mixture shown in Table 1 is carried out together with bis fatty acid amide,
The two types of polystyrene resin particles can be mixed well.

Claims (2)

[Claims] (1) A molded resin for a spool of a photographic film cartridge, characterized in that a bis fatty acid amide is dispersed in a kneaded mixture of a general-purpose polystyrene resin and an impact-resistant polystyrene resin. (2) Molding for a spool of a photographic film cartridge characterized by mixing general-use polystyrene resin particles and impact-resistant polystyrene resin particles with a bis-fatty acid amide and melt-kneading to obtain a polystyrene resin kneaded product in which the bis-fatty acid amide is dispersed. Method of manufacturing resin.