JPH0732613A - Ink holding body and ink storage container packed with ink holding body - Google Patents

Abstract

PURPOSE:To provide an ink storage container packed with an ink holding body, which is used for the ink jet type printer and the like and which can be easily reutilized by crushing and remelting the same including the ink holding body without disassebling it. CONSTITUTION:A heat-meltable polyurethane foam obtained by adding 1 pt.wt. of a triethylamine as a catalyst, 1 pt.wt. of a silicone compound as a foam stabilizer and a predetermined amount (an isocyanate index = 100) of an allophanate-modified TDI prepared to 29.0wt.% of an NCO content to 100 pts.wt. of a polyether polyol having 2,000 molecular weights and by stirring them to be foamed is subjected to the membrane melt treatment. An ink holding body is processed by using this foam thus treated and is packed in a container made of polystyrene to obtain an ink storage container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink holder for holding ink to be supplied to a print head of an ink jet printer or the like and a material having the ink holder filled therein for easy reuse. Regarding the ink container.

[0002]

2. Description of the Related Art Ink jet printers, copiers, facsimiles, etc. are used in which an ink container made of polyurethane foam is filled in an ink container made of a thermoplastic resin in order to facilitate the supply of ink. (Japanese Patent Laid-Open No. 5-38816). Instead of polyurethane foam, cotton, felt, etc. made of thermoplastic synthetic fibers are also used. Since polyurethane foam has a large volume of pores capable of holding ink and has a small compression set, it has an excellent ability to maintain its shape in an ink container. However, conventional polyurethane foams that have been used as ink holders are difficult to reuse because they are thermosetting, and in order to reuse an ink container made of thermoplastic resin, the container must be disassembled. Then, the ink holder in the container must be taken out, and even if this troublesome disassembling work is carried out to recover the container, there is not much economic merit. On the other hand, cotton, felt, and the like made of thermoplastic resin synthetic fibers can be reused by melting with an ink container, and it is particularly preferable to use a container made of the same resin as the fibers because reuse is easier. However, since the above-mentioned cotton and felt have a small pore volume capable of holding ink and have low rigidity and are difficult to maintain their shape, permanent deformation occurs while they are in contact with ink, and the volume that holds ink is further reduced. However, the stable ink supply cannot be maintained.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above problems of the conventional ink holder and ink container, maintains good ink holding ability for a long time, and disassembles the ink container. It is an object of the present invention to provide an ink holding body and an ink holding container that can easily reuse the entire ink holding container including the ink holding body filled in the container.

[0004]

The ink carrier according to the first aspect of the present invention is characterized by comprising a heat-meltable polyurethane foam obtained by foaming a foamable composition containing alohanate isocyanate and a polyol as main components. And The second invention is characterized in that the alohanate conversion of the alohanate isocyanate is 40 to 70% by weight, and the heat melting temperature of the heat fusible polyurethane foam is 190 ° C. or higher. Further, the ink container of the third invention is characterized in that the ink holder is filled in a container made of a thermoplastic resin.

The above-mentioned "arohanate isocyanate" has a structure in which 1 mol of isocyanate is added to urethane as shown in the following formula. RNCO ₂ R '+ RNCO (or 2 RNCO + R'O
H) = RNHCO-N (R ) CO 2 R ' allophanate conversion of polyisocyanates in the present invention is preferably in the range of 40 to 70 wt%. The above-mentioned alohanate isocyanate includes a bond such as urethane, urea, and burette in addition to the alohanate bond. The alohanate conversion rate is a value (unit:% by weight) obtained by GPC (gel permeation chromatography) measurement, and is calculated by the following formula. Conversion rate (% by weight) = [alohanate isocyanate amount (parts by weight) / total isocyanate amount (parts by weight)] × 100 Polyisocyanate conversion rate is 70% by weight
If it exceeds 10, the viscosity of the "foamable composition" tends to be high, and it tends to be difficult to handle. If it is less than 40% by weight, the concentration of alohanate groups in the polyisocyanate tends to be low, and the heat melting property at high temperature tends to decrease. It is in. This conversion rate is particularly preferably in the range of 45 to 60% by weight. This is because the foamable composition has an appropriate viscosity when mixed with other components such as a polyol to form a foam, and easily melts by heat melting or kneading to develop thermoplastic (melting) characteristics. This is because it is completely compatible with the thermoplastic resin.

As the polyisocyanate for producing the above-mentioned allohanate isocyanate, aromatic TD is used.
I, MDI, Polymeric MDI, NDI, PPDI,
XDI, TMXDI or aliphatic HDI, H12M
DI, IPDI, LDI, IPC, hydrogenated XDI, CHD
I, TODI, and modified products thereof can be used. Of these, use of TDI, MDI, IPDI and modified products thereof is suitable. Further, the conversion of polyisocyanate to alohanate isocyanate can be carried out at a desired rate by selecting various raw material compositions, heating conditions, pressurizing conditions and the like. For example, the heating temperature is preferably 20 ° C. or higher, particularly 70 to 100 ° C.
A method for producing alohanate isocyanate is described in JP-A-46-1671. In this publication, an ink holder which is melted at a high temperature and excellent in reusability and a filling method thereof are used. There is no suggestion of making such ink containers.

As the above-mentioned "polyol", known polyols such as polyether polyol or polyester polyol can be used. This polyether polyol has a molecular weight of 1,000 to 10,000,
A bifunctional or trifunctional one obtained by reacting an initiator such as water, propylene glycol, ethylene glycol or glycerin, hexanetriol, triethanolamine and the like with ethylene oxide, propylene oxide or the like is preferable, and the polyester polyol has a molecular weight of 1
2 or 3 obtained by dehydration condensation reaction of adipic acid with glycol or triol of 000 to 5000
Sensory ones are preferred. Further, a polyether polyol that does not cause deterioration of the ink holding body regardless of whether the ink component is alkaline or acidic is particularly preferable.

The above-mentioned "heat-meltable polyurethane foam"
Examples of compounding raw materials other than the above-mentioned main components for producing (hereinafter referred to as heat-meltable foam) include known polyurethane plasticizers (for example, DOP, DBP, TOP, etc.), foaming agents (water, HCFC, air, Nitrogen, pentane, methylene chloride, nitroalkane, formic acid, etc.), flame retardants (known compounds such as TCPP and other phosphorus halides) can be used, and further, dispersants, cell open agents (polyether siloxane, sulfonated ricinoleic acid). Known substances such as sodium) can be used. The isocyanate group / hydroxyl group (equivalent ratio) (isocyanate index) of the foamable composition is 70 or more, particularly 80 as in the isocyanate index of ordinary polyurethane foams.
The above is preferable.

At present, polyurethane foam is generally used as the ink holder. Polyurethane foam has a large pore volume and a large ink holding force, but since a cell film is formed on the foam, the ink holding force or supply ability may vary. Therefore, it is preferable that the heat-fusible foam constituting the ink holder of the present invention has a cell film removed by a melt treatment. As the film-melting treatment, a chemical method of immersing in an alkaline aqueous solution and a physical method of containing the heat-meltable foam in a pressure vessel and igniting an explosive gas such as hydrogen and oxygen to instantaneously remove the cell film are used. There is a method.
By this film-melting treatment, the thermofusible foam has a three-dimensional network structure with the cell film removed, and is suitable as a material for holding ink.

The number of cells of the heat-meltable foam before the above-mentioned melt film treatment is preferably in the range of 10 to 60 cells / inch. This heat-fusible foam is compressed and filled in an ink storage container as an ink holder, and the compression rate at the time of compression filling is set according to the number of cells, and within the preferable number of cells, the number of cells is small. If the volume of the ink container is 1, the range of 15 to 2 (volume ratio) is preferable. As described above, the number of cells and the compression rate are selected in consideration of the correlation, but if the number of cells is less than 10 cells / inch, a homogeneous foam will not be formed even at a high compression rate close to 15, and capillary phenomenon will occur. Since it does not work very much, the function as an ink holder is deteriorated, which is not preferable. Also, the number of cells is 60
When the number exceeds 5 / inch, even if the compression ratio is close to 2, the amount of ink held becomes small and the ink supply capability is reduced, which is not preferable.

The "thermoplastic resin", which is the material of the container for accommodating the ink holder of the present invention, is not particularly limited, and polystyrene (referred to as PS), acrylonitrile butadiene styrene copolymer (referred to as ABS), polyethylene (referred to as PE). A thermoplastic resin such as polypropylene (referred to as PP) can be used. The mixture obtained by pulverizing or melting these thermoplastic resins and the thermofusible foam constituting the ink carrier is a partial compatibilization of the thermoplastic resin and the thermofusible foam, and the physical properties of the thermoplastic resin used are Little decrease. Especially when polystyrene resin is used,
Due to the inherent effect of the mixed thermofusible foam as an elastomer, the impact resistance of the recycled product is rather improved, and the thermoplastic resin can be reused as a raw material for usual applications. In addition, by adding an unused thermoplastic resin when molding the recycled product, by changing the ratio of the heat-meltable foam and the resin,
The physical properties and the like can be adjusted according to the purpose and purpose of reuse.

[0012]

[Function] Polyurethane foam is widely used for molded articles and the like which are compounded with thermoplastic resin. However, the ink holding inside the ink container for supplying the ink to the print head of the ink jet type printer is retained. It has been put to practical use as a body. However, since the polyurethane foams used so far are thermosetting,
This ink container can not be heated and melted as it is and cannot be pelletized, or it cannot be re-molded, and in order to be reused, it is crushed as it is and the foam and the resin are separated and reused, respectively, or The ink container is disassembled into an ink holder and a container, and the polyurethane foam that composes the ink holder is chemically treated such as decomposing into a polyol by glycolysis, or crushed and re-adhered to form a core material or carpet underlay. Will be used as. However, in all of these methods, the process is complicated and the recovery efficiency is not excellent, and in consideration of economic efficiency, the meaning of reuse is not so significant. On the other hand, since the ink carrier of the present invention is thermoplastic (melting), it melts and flows at a predetermined temperature, and has excellent compatibility with ordinary thermoplastic resins, so that it is ground or crushed together with a container made of thermoplastic resin. A uniform polyblend is obtained by remelting and pelletizing as it is. Therefore, both the ink holder and the container can be reused very easily and efficiently.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples. (1) Preparation of Alohanate Isocyanate 2,4-TDI (Nippon Polyurethane Co., Ltd., trade name “TD
I-80 ") was used under the following conditions. The NCO value of the obtained alohanate isocyanate was 29.0%, the viscosity was 5000 mPa · s, and the alohanate conversion rate was 31.5% by weight. The conversion rate of alohanate is a value (unit:% by weight) obtained by GPC measurement, and was calculated by the following formula. Conversion rate (wt%) = [alohanate isocyanate amount (parts by weight) / total isocyanate amount (parts by weight)] × 100 Incidentally, this GPC measurement was carried out as follows. That is, about 10 mg of the produced alohanate isocyanate
Was precisely weighed and dissolved in 10 ml of THF (tetrahydrofuran) to adjust the concentration to 0.1% (wt / vol). The composition of this solution was examined by GPC using THF as an eluent, polystyrene gel as a packing material, and a column having a size of 8φ × 300 mm, and the amount of alohanate isocyanate was determined. [Synthesis conditions] Predetermined amount of diethylene glycol (DEG)
Is maintained below 70 ° C. and added to 2,4-tolylene diisocyanate (2,4-TDI) under a stream of nitrogen. Then, acetylacetone zinc, which is an alohanation catalyst, was added to the reaction mixture, and the reaction was carried out for a predetermined time while maintaining the temperature at 70 ° C. to obtain a modified isocyanate having an NCO value of 29.0%.

(2) Production of heat-meltable foam Polyether polyol (manufactured by Sanyo Kasei Co., Ltd., trade name "PL
2100 ", molecular weight: 2000) 100 parts by weight of triethylamine as a catalyst, 1 part by weight of a silicone compound (Toshiba Dow Corning Silicone, trade name" SF2961 ") as a foam stabilizer, and 3 parts of water as a foaming agent. After adding parts by weight and stirring, a predetermined amount (isocyanate index = 100) of alohanate-modified TDI adjusted to an NCO content of 29.0% was added and stirred to obtain a hot-melt foam.

(3) Melt film treatment The heat fusible foam produced in the above (2) was treated with 30 × 30 × 3.
After cutting to a size of 0 cm, enclose it in a closed container,
The ratio of oxygen and hydrogen in the container is 1: 2 and the pressure is 9.8 × 1.
The liquid film treatment was performed by substituting with a mixed gas of 0 ⁴ Pa and igniting. The degree of the molten film can be adjusted by the pressure of the gas to be filled (up to 2.9 × 10 ⁵ Pa).

(4) Processing of Ink Holder and Kneading with Thermoplastic Resin An ink holder similar to the current product was processed using the heat-meltable foam subjected to the melt film treatment in (3) above. Simulating the case of reusing an ink container filled with this ink holder, this ink holder is made of thermoplastic resin polystyrene (PS), acrylonitrile butadiene styrene copolymer (ABS), polyethylene as shown in Table 1. (PE) or polypropylene (PP) together with a grinder, and using a conical mixer for 3 to 5 minutes, 20
Melt kneading was carried out at 0 ° C. After kneading, the mixture of the hot-melt foam and the resin taken out is molded into a sheet by a compression molding machine, crushed by a crusher to a particle size of about 2 to 3 mm, dried, and then dried by an injection molding machine. It was formed into a 3 mm sheet. Further, in place of the ink holder made of the above heat-meltable foam, a current ink holder made of thermosetting polyurethane foam (hereinafter referred to as thermosetting foam) manufactured by INOAC CORPORATION under the product name "CFH-40" is used. ] Was used to form a sheet-like body in the same manner as above. Table 1 shows the types of thermoplastic resins and heat-meltable foams or currently used thermosetting foams used in each test example, and their blending amounts. The amount of foam blended with 100 parts by weight of resin was 3 parts by weight and 6 parts by weight (only PS and ABS) in this test example.

[0017]

[Table 1]

Test Examples 1, 4, 7 and 9 are comparative test examples using only the thermoplastic resin, and Test Examples 11 to 14 are thermosetting foams used as the above-mentioned ink-holding material for the above-mentioned thermoplastic resins. It is a comparative test example mixed with a resin, and another test example is a test example in which the ink carrier of the present invention is mixed with each thermoplastic resin. Table 2 shows the results of measuring the physical properties of the sheet-like body molded using the compound of each test example and observing the state of dispersion of the resin and foam. The tensile strength and elongation at break in Table 2 are JIS K 7113 (PS, AB
S is the breaking strength, PE and PP are the yield strengths), and the Izod impact value was measured according to JIS K7110.
The dispersed state was observed by a scanning electron microscope at a magnification of 5000 times (observation result: ◯ is compatible, Δ is partially separated, × is almost separated). All the above measurements and observations were performed at room temperature.

[0019]

[Table 2]

According to the results shown in Table 2, in Test Examples 2, 3, 5, 6, 8 and 10 using the heat-meltable foam, the elongation at break is 40 to 70% as compared with the thermoplastic resin alone. Although relatively low, the retention of tensile strength and Izod impact strength is as high as about 80 to 90%. Such results are the same for PS, ABS, PE, and PP, regardless of the type of resin, except for the Izod impact value of PS.
Incidentally, the Izod impact value of PS is 110, 6 when blending 3% of heat-melting foam when the plainness is 100.
% When the blending ratio is 116, which is an improvement in impact strength that is usually observed when an elastomer is blended with a thermoplastic resin. Therefore, the ink container is PS
The present invention is considered to be most useful when molded with. It was also confirmed by observation with a scanning electron microscope that the state of dispersion of the heat-meltable foam in each resin was good regardless of the type of resin. In the current ink container, the weight ratio of the ink holder is about 23.
% (Weight% of the ink holder relative to the total weight of the container and the ink holder, excluding the head for ejecting ink integrated with the ink cartridge and the metal-based circuit)
However, based on the results of the above test example, by adding an appropriate amount of unused resin in consideration of the purpose of reuse and the purpose of reuse, it can be reused without disassembling the ink holder and container in the actual product. It is thought that it can be done.

On the other hand, in Comparative Test Examples 11 to 14, although the blending amount of the thermosetting foam was as small as 3% by weight, the retention rate of the tensile strength of PS and ABS was as high as about 90%. The values are greatly reduced, and the retention rates of elongation at break of PE and PP are extremely low at 25% and 23%, respectively.
The other retention ratios are about 40 to 60%, which is much lower than that of the thermoplastic resin alone. Further, according to the observation with a scanning electron microscope, it was found that the foam was thermosetting and was not compatible with the resin at all, and the foam and the resin were completely separated. The present invention is not limited to the specific examples described above, and various modifications may be made within the scope of the present invention depending on the purpose and application. For example, a thermoplastic resin other than the above may be used, or an appropriate compatibilizer may be added during the melt processing.

[0022]

EFFECT OF THE INVENTION The ink holder of the present invention and the ink container filled with the ink holder are made of a thermoplastic resin, and the ink container is made of a thermoplastic resin. It is possible to recycle by crushing or remelting, including the ink holder inside, without disassembling. Since the thermofusible foam used has a very good compatibility with a thermoplastic resin such as polystyrene, it can be used as a raw material resin for ordinary resin moldings as it is or by appropriately blending an unused thermoplastic resin.

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Claims (3)

[Claims] 1. An ink carrier comprising a heat-meltable polyurethane foam obtained by foaming a foamable composition containing an alohanate isocyanate and a polyol as main components. 2. The ink carrier according to claim 1, wherein the alohanate conversion of the alohanate isocyanate is 40 to 70% by weight, and the heat melting temperature of the heat fusible polyurethane foam is 190 ° C. or higher. 3. An ink storage container in which the ink holder according to claim 1 or 2 is filled in a thermoplastic resin container.