JPS6315307B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is a method of incinerating fine fibers (hereinafter referred to as paper sludge) that are contained in papermaking waste liquid during the process of manufacturing recycled paper using waste paper as a raw material, and converting it into ash. , relates to a method of manufacturing a resin composition by effectively utilizing the paper sludge ash. [Prior art and problems] Waste paper such as newspaper, paperboard, and corrugated paper is disintegrated using a disintegrating machine such as a kneader to remove tough fiber substances that do not disintegrate easily and impurities such as dirt and strings mixed therein. It is generally used to recycle the waste paper pulp that is subsequently obtained into paper stock. In this case, a large amount of fine fibers, which cannot be made into paper, are generated due to the disintegration operation of the waste paper, and these fibers remain in the waste liquid during the papermaking process, which poses a problem in how to dispose of them. Therefore, the present applicant has actively utilized the above-mentioned waste paper sludge as a resource, focusing in particular on the fact that it is possible to produce inexpensive resin compositions by using it as a compounding material for thermoplastic resin. He invented a method for producing a resin composition and filed it as Japanese Patent Application No. 114071/1983 (Japanese Patent Publication No. 10503/1983). In this application, paper sludge remaining in the waste liquid from the papermaking process is dried in a separate process, a resin composition is produced using the dried paper sludge as a raw material, and the resin composition is further molded into a pressed sheet. That is,
The process is shown as a flow sheet in Figure 3,
In the figure, 13' is a tank for paper sludge, 14' is a silo for resin pellets, 15' is a scale, 16' is a hot mixer, 17' is a cool mixer, 18' is a crusher, 19' is a storage tank, and 20'24' is a sheet extrusion molding machine, 24' is a conveying roller, and 21' is a cutter. The paper sludge tank 13' stores dried paper sludge, while the resin pellet silo 14' stores thermoplastic resin, such as pellets or powder of polyethylene, polypropylene, polyvinyl chloride, polystyrene, ABS resin, etc. resin is stored. The paper sludge and resin are each weighed using a scale 15' and then charged into a hot mixer 16'. In this case, it is desirable that the blending ratio of paper sludge be 50% by weight or less of the total weight. Inside the hot mixer 16', the paper sludge and resin are heated and melted while being stirred and mixed, thereby uniformly kneading the paper sludge and the molten resin. This kneaded fluid is then passed through cool mixer 1.
7', and air-cooled while stirring in the cool mixer 17' to form a lump. This lump is then pulverized by a pulverizer 18' and then stored in a storage tank 19'. When manufacturing an extruded sheet using the resin composition thus obtained as a raw material, the resin composition is supplied to the sheet extrusion molding machine 20' via the hopper 22', and is After heating it to a semi-molten state, it is extruded from the die 23',
After cooling on the conveying roller 24', cutter 2
1' to cut it into an appropriate length. However, in the series of manufacturing steps described above, the raw materials must be mixed, heated, melted, cooled, and pulverized before the resin composition is sent to the sheet extrusion molding machine 20'. This required considerable expense. Moreover, paper sludge is sensitive to high heat, so when kneading it with resin in the sheet extrusion molding machine 20' and applying heat to make it into a semi-molten state, there are inevitably restrictions on the temperature, which limits the molding conditions. It has its own limitations and has the drawback of being difficult to apply to resin products that require a high melting temperature. [Objective and Structure of the Invention] The object of the present invention is to incinerate the paper sludge remaining in the waste liquid during the papermaking process to turn it into ash, and use this as a compounding material for thermoplastic resin, thereby converting the above-mentioned waste into ash. We aim to actively utilize certain paper sludge as a resource, simplify work, simplify equipment, and reduce costs in the process of molding resin compositions, and furthermore, do not impose any restrictions on molding conditions, especially temperature conditions. In order to achieve this objective, the present invention aims at expanding the molding conditions, and in order to achieve this objective, in the process of recycling waste paper pulp obtained by disintegrating waste paper into paper stock through a paper making process, the waste paper discharged in the paper making process is Paper sludge is incinerated to form ash, and the paper sludge ash is mixed with a heat-melted thermoplastic resin at an appropriate blending ratio, which is further heat-melted and kneaded. [Example] Fig. 1 shows a flow sheet from collecting paper sludge contained in papermaking waste liquid to drying and incinerating it to obtain paper sludge ash in the process of manufacturing recycled paper from waste paper. Dehydrator, 2 is a receiving conveyor, 3 is a horizontal paddle mixer, 4 is a vertical fluidized dryer, 5 is a cyclone, 6 is a hopper, 7
is a distribution damper, and 8 is an incinerator. The papermaking waste liquid is first put into a centrifugal dehydrator 1, and the paper sludge contained in the waste liquid is centrifugally dehydrated. The moisture content of the paper sludge thus recovered is approximately 50-80%. The collected paper sludge is then sent to a paddle mixer 3 by a receiving conveyor 2. Inside the paddle mixer, there are a pair of screw type stirring blades 3a, 3a.
are arranged parallel to each other and intersect with each other, and the paper sludge is stirred and separated by the rotation of both stirring blades and is fed forward. The paper sludge transferred through the paddle mixer 3 is then conveyed to the fluidized fluid dryer 4 via a push-type screw conveyor 9. An impeller 10 is disposed at the inner bottom of the fluidized fluid dryer, and hot air is blown into the inner bottom through an air supply pipe 11, so that the paper sludge carried into the fluidized fluid dryer 4 is is dried with hot air while being raked up by the rotation of the impeller 10. At this stage, the moisture content of the paper sludge is approximately 10%. The dried and lightened paper sludge is blown up by the wind force generated by the rotation of the impeller 10 and the wind pressure of the hot air, and is sucked into the cyclone 5 through the outlet pipe 12 installed at the top of the fluidized fluid dryer. Then, it is collected and settled by the cyclone 5, dropped into a hopper 6, and then sent to an incinerator 8 via a distribution damper 7.
Then, it is incinerated in the incinerator at a temperature of about 800 to 900°C, and the paper sludge ash is taken out. Note that a part of the paper sludge is returned to the paddle mixer 3 via the distribution damper 7 and mixed with the paper sludge with a high water content conveyed by the receiving conveyor 2, whereby the paper sludge in the paddle mixer 3 becomes powdery. The drying efficiency in the fluidized dryer 4 is increased. Figure 2 shows a flow sheet for manufacturing a resin composition using paper sludge ash after incineration of the paper sludge as a raw material and supplying it to an extrusion molding machine. sludge ash tank,
14 is a silo for powdered resin, 15 is a measuring device, 16 is a tumbler, 17 is an extruder, 18 is a cooling water tank, 19 is a cutter, and 20 is an extrusion molding machine. Ash after incineration is stored in a paper sludge ash tank 13, and a silo 14 for powdered resin is stored.
thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, polystyrene,
Powdered resin such as ABS resin is stored.
The paper sludge ash and resin are each weighed using a scale 15 and then put into a tumbler 16. In this case, it is desirable that the blending ratio of paper sludge ash be about 30% of the total. Inside the tumbler 16, the paper sludge ash and the powdered resin are mechanically stirred to mix them together, but since the ash is brittle, it becomes very fine and mixes well and becomes uniform. This mixed powder is then poured into an extruder 17, heated in the extruder 17, extruded in a semi-molten state, passed through a cooling water tank 18, and cut by a cutter 19 to form pellets. When manufacturing a molded article using an injection molding machine using the resin composition obtained in this way as a raw material, the pellet-shaped resin composition is supplied to the injection molding machine 20 via the hopper 22, as in a general injection molding machine. The material is then heated to a semi-molten state in the machine, extruded from a die 23, cooled on conveying rollers 24, and then cut into appropriate lengths by a cutter 21. Next, the characteristics of the resin composition according to the present invention and a conventional thermoplastic resin (A) and a resin composition (B) mixed with paper sludge were compared, and the results are shown in the following table.
The thermoplastic resin tested was polypropylene.
In the present invention, the blending ratio of the polypropylene resin and paper sludge ash is 70% by weight: 30% by weight.

[Table] From the results, the product of the present invention has a slightly higher specific gravity than polypropylene alone, which is almost equivalent to the resin composition mixed with paper sludge, and the tensile strength is higher than either, and the elongation and Although the impact strength was lower than that of polypropylene alone, the flexural modulus and flexural strength were higher, indicating that the rigidity was increased. Note that the resin composition according to the present invention is not limited to the extrusion molded products shown in the above examples, but can also be used for other injection molded products,
Of course, various resin compositions such as compression and vacuum can also be applied. [Effects of the Invention] As explained in the embodiments above, the present invention incinerates paper sludge that has been discarded because it cannot be used even when waste paper is used as a raw material for recycled paper, and the ashes are used to create a resin composition. This eliminates the pollution problem associated with the conventional disposal of paper sludge, eliminates waste in processing operations and processing costs, and allows the paper sludge itself to be used as industrial waste. Since it is available at a low price, manufacturing costs can be significantly reduced. Furthermore, compared to the conventional method of mixing paper sludge as it is to form a molded product, the process of making the resin composition to be fed to an extrusion molding machine is simpler, and the equipment used during this process is simplified, resulting in significant cost savings. Furthermore, since the paper sludge ash after baking the paper sludge is mixed into the resin, it is not affected by temperature, so it can be mixed into various resins with high melting points that cannot be mixed directly with paper sludge. Therefore, the molding conditions are not restricted. Additionally, resin-processed products made from this resin composition have excellent properties in terms of rigidity, especially tensile strength, so they can be utilized in many ways as an alternative material to conventional resin-processed products and paper-processed products. It is extremely useful industrially because it has many advantages such as being applicable to various purposes.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention. Figure 1 is a flowchart of the manufacturing process from collecting paper sludge in papermaking waste liquid to incinerating it into ash, and Figure 2 is a flowchart of the manufacturing process using paper sludge ash. FIG. 3 shows a flow sheet for manufacturing a resin composition using conventional paper sludge and extrusion molding. 4...Fluidized fluid dryer, 8...Incinerator, 16...
tumbler.

Claims (1)

[Claims] 1. In the process of recycling waste paper pulp obtained by disintegrating waste paper into paper stock through a paper making process, the paper sludge discharged in the paper making process is incinerated to form ash, and the paper sludge ash and thermoplastic resin are 1. A method for producing a resin composition, characterized in that the mixture is mixed at an appropriate blending ratio, heated and melted, and kneaded.