JPH04146290A - Press roll for paper making machine - Google Patents

Abstract

PURPOSE:To obtain the title roll having excellent surface smoothness, releasability of wet paper, surface hardness, roll strength, uniform surface characteristics, being planished, usable as a stone roll substitute, comprising specific constitution. CONSTITUTION:The outer periphery of a metal core material 2 is provided with a substrate layer 4 comprising a metallic material (preferably Ni-Cr alloy) having a coefficient of thermal expansion lower than the constituent metal material of the core material 2, the outer periphery of the substrate layer 4 is supplied with a ceramics layer 3 and a releasable organic polymer substance made of a synthetic resin or wax is packed into gaps among ceramic particles at least on the surface layer part of the ceramics layer 3 to give the objective roll. The objective roll, for example, is obtained by subjecting metal powder to gas spraying to the outer periphery of the core material 2 to form a layer 4, subjecting a metal oxide to plasma spraying to form a layer 3, then impregnating the surface of the layer 3 with a solution of synthetic resin and curing.

Description

[Detailed Description of the Invention] The industrial application field of the invention is a press roll for a paper machine.
The present invention relates to a press roll for a paper machine that is used in the press part of a paper machine to squeeze water from wet paper and impart smoothness to its surface.

BACKGROUND OF THE INVENTION Conventionally, roll presses and extemporized nipple presses (ENPs) have been known as representative methods for pressing wet paper webs in the press section of a paper machine.

Among these, the roll press is a method in which wet paper is held on felt and passed between two pressurized rotating rolls to extract water, while the ENP is a method in which wet paper is held on felt and squeezed out. In this method, water is squeezed by passing between a rotating roll and a belt pressurized by a pressure shoe with a wide nip width.

In both methods, a rotating roll with a hard surface is used in terms of pressurizing effect and smoothness. It is used in combination as a roll.

It is desired that such a rotating roll with a hard surface can withstand high loads, high speed rotation, and long-term use. To meet this demand, stone rolls (granite rolls) made of natural granite have been widely used. This stone roll generally has a mirror-like surface finish, has a high surface hardness, is less abraded by the doctor blade that is usually attached to remove paper waste, and has good paper layering of wet paper. In addition, it has excellent properties such that the pitch contained in the valve is difficult to adhere to even when used for a long period of time, and has the advantage that paper breakage during pressing is less likely to occur.

Problems to be Solved by the Invention However, since the above-mentioned stone rolls are manufactured using natural stones, they are expensive and require long delivery times due to the difficulty in obtaining such stones due to the recent trend of resource depletion. There has been a problem in that it is extremely difficult to quarry, transport, and process large stones needed for stone rolls, which have recently become increasingly longer and larger.

Furthermore, because the material is polycrystalline natural stone, there are variations in surface properties (e.g. porosity, surface hardness, water retention, etc.) for each roll manufactured, or even for the surface of a single roll. However, there was an essential problem in that variations in surface properties were often observed.

The purpose of this invention is to solve the above-mentioned problems of the prior art, to be usable in place of the conventional stone roll, and to
The smoothness of the roll surface is improved and there are no voids on the surface of the ceramic layer, so the release property of the wet paper is improved, and the wet paper does not stick and can be released stably. In addition, it is difficult for pitch to adhere even after long-term use, and to give the wet paper smoothness after pressing, a mirror-like finish is possible, and the doctor blade for removing paper scraps makes the surface difficult to wear. It has hardness and roll strength that can withstand high loads and high speed rotation for a long period of time, and the roll surface characteristics are homogeneous, making it easy to set and manufacture excellent surface characteristics. We are trying to provide press rolls for paper machines.

Means for Solving the Problem In order to achieve the above-mentioned object, the present invention provides a base layer made of a metal material having a coefficient of thermal expansion smaller than that of the metal material constituting the core, on the outer periphery of the metal core. A press roll for a paper machine, in which a ceramic layer is provided on the outer periphery of a base layer, and gaps between ceramic particles at least in the surface layer of the ceramic layer are filled with an organic polymer substance having mold release properties made of synthetic resin or wax. The gist is:

The metal core used in this invention is, for example, iron,
These include stainless steel, copper, and brass.

A base layer made of a metal material layer having a coefficient of thermal expansion smaller than that of the surface material of the metal core and larger than that of ceramics is formed on this metal core.

The purpose of this base layer is to integrate the metal core and the ceramic layer and to prevent corrosion of the core.

The base layer made of this metal material layer has a thermal expansion coefficient smaller than that of iron-based metals and copper-based metals, and is usually suitable if the thermal expansion coefficient is about 9X10=℃/12X 10-''℃. To give specific examples, molybdenum metals and nickel metals are suitable in terms of corrosion resistance, and it is particularly preferable to use nickel-chromium alloys and nickel-chromium-aluminum alloys.

This metal material layer is formed by a gas spraying method or a gas plasma spraying method using metal powder.

The thickness of this base layer is approximately 100 to 500 mm.

This base layer acts as a kind of buffer material in terms of thermal expansion, and improves the peelability between the core and the ceramic layer due to thermal expansion.

Note that, if necessary, from the viewpoint of maintaining the anticorrosion properties of the core, an anticorrosive coating may be further formed between the base layer and the core.

Examples of the material for such an anticorrosive coating include nickel, nickel-aluminum alloy, copper, stainless steel, etc., and the thickness thereof is preferably 100 to 500 mm.

In the above-mentioned structure of the present invention, the ceramic layer is usually made of powder of various metal oxides, which is coated with a base layer by a plasma spraying method (water-stabilized plasma spraying method, gas plasma spraying method, etc.). It can be easily formed by coating the outer periphery of the core body.

Gray alumina (94
%AI O-2, 5% T t O2) white alumina (99% A1203), titania (TiQ), alumina/titania (A1203 TiO), mullite (AI 20s Sio), zirconia/mullite (A1203ZrO-5in2), etc. are typical, and these can be used alone or in combination.

Furthermore, other thermally sprayed metal oxides, low melting point alloys, metal carbides, metal nitrides, etc. can also be mixed and used.

The particle size of this thermal spray material is suitably 10 to 200p.

As the plasma spraying device, a water stabilized plasma spraying device using water as a plasma source, a gas plasma spraying device using argon, helium, hydrogen, nitrogen, etc. as a plasma source, etc. are used.

In addition, when thermally spraying the thermal spraying material, a uniform ceramic layer can be formed by rotating the core body, which is a non-thermal sprayed body.

The thickness of the ceramic layer formed varies depending on the dimensions of the roll, the pressing force, etc., but is usually 1 to 30 mm.

The surface of the ceramic layer thus formed is coated with a raw material or solution of an organic polymeric substance having mold releasability, such as synthetic resin or wax, using a coater, brushing, spraying, etc., and is coated between the ceramic particles. Penetrates into the interstices and becomes impregnated.

Thereafter, the synthetic resin or wax is densely filled into the gaps between the ceramic particles by curing the synthetic resin raw material by a curing reaction or by volatilizing the solvent of the synthetic resin or wax solution.

Specific examples of organic polymer substances having such mold release properties include epoxy resins, phenol resins, polyurethane resins, silicone resins, fluororesins, and waxes.

Considering that this organic polymer substance having mold release properties penetrates, impregnates, and fills the gaps between ceramic particles, it is preferable to use one with low viscosity in the raw material or solution stage. . For example, when using an epoxy resin as an organic polymer substance with mold releasability,
The viscosity of the resin raw material is, for example, 50 to 500 cps.

Second, if the epoxy resin raw material is less than 50 cps, it is difficult to obtain, and if it exceeds 500 eps, it becomes difficult to penetrate into the gaps between ceramic particles.

In addition, as organic polymer substances with mold release properties, other phenolic resins, polyurethane resins, silicone resins,
When using fluororesin, wax, etc., check the viscosity of the raw material or the solution diluted with an appropriate solvent.
It needs to be as low as possible.

Such an organic polymeric substance having mold releasability made of synthetic resin or wax is filled into the gaps between ceramic particles in at least the surface layer of the ceramic layer, but it is difficult to regrind during use as a press roll for a paper machine. In consideration of this, it is desirable that such a synthetic resin or wax be filled in 1/4 to 1/2 of the surface of the ceramic layer.

The surface of the roll having a ceramic layer coated with an organic polymer substance having mold releasability is further ground.
Surface roughness (JIS B 0801
A press roll for a paper machine having a diameter of 0.2 to 2.0 μm (Ra) is obtained.

Function: According to the above-mentioned press roll for a paper machine, the gap between the ceramic particles in at least the surface layer of the ceramic layer provided on the outer periphery of the base layer of the metal core has mold releasability made of synthetic resin or wax. Since it is filled with an organic polymer substance, it can be used in place of conventional stone rolls, and the roll surface has improved smoothness, and there are no voids on the surface of the ceramic layer, which improves the releasability of wet paper. As a result, wet paper does not stick and can be released stably.

In addition, it is difficult for pitch to adhere even after long-term use, and to give the wet paper smoothness after pressing, a mirror-like finish is possible, and the doctor blade for removing paper scraps makes the surface difficult to wear. It has hardness and roll strength that can withstand high loads and high speed rotation for a long period of time, and the roll surface characteristics are homogeneous.

Embodiments Next, embodiments of the present invention will be described in detail based on the drawings.

Example First, as the metal core (2) of the press roll (1) for a paper machine, a cast iron cylindrical body (thermal expansion coefficient 14) with a length of 600 am, a surface length of 5.000 mm, and a diameter of 490
．． OX to-6/'C) was used. This core (2)
The surface is cleaned and degreased with an organic solvent (Trichlene), and then rust and foreign matter are removed by sandblasting.
The surface is roughened, and nickel-chromium alloy powder (particle size 10~44 mm) is injected onto the outer periphery of the core (2) using a gas injection device (gas used is oxygen-acetylene) while rotating. As a result, a base layer (4) having a thickness of 100 Jm was formed.

Next, while rotating the core body (2) having the base layer (4), gray alumina powder having an average particle size of 50 mm was injected into the core body (2) using a water plasma injector over a period of 6 hours to obtain a thickness of 5.3 cm. A ceramic layer (3) made of gray alumina powder was formed.

Note that the water plasma 8 irradiation conditions are as follows.

Input type crab 400V, 400A (350KVA) Injection gun: 380V, 420A Gray alumina powder feeding rate: 40Kg/hr (approx. 230Kg) Distance between injection gun and core = 300-400filIIl Traverse speed: 10-20+u+/ Effective deposition amount of sec gray alumina powder: Approximately 50% Next, the surface of the ceramic coated roll thus formed was preheated, and 100% by weight of the preheated epoxy resin raw material (base material: Pernox 10B) with a viscosity of 100 to 200 cps was added. 80 parts by weight of hardening agent Bellcure HV19, 4 parts by weight of accelerator (manufactured by Nippon Bellnox Co., Ltd.) were applied to the ceramic layer (3 parts by weight) using a coater.
) A resin layer (6) was formed by coating the surface and filling the gaps between the ceramic particles and curing.

Next, the surface of the roll coated with epoxy resin is polished using a diamond grinding wheel.
Surface roughness 0.5Jm (Ra
), a press roll (1) for a paper machine of the present invention having a roll outer diameter of 500.2 cm was obtained.

The press roll (1) thus obtained was made of high-quality paper and was subjected to a linear pressure of 90 kg/cm.

When used at a speed of 800 m/min, it was confirmed that the wet paper could be used without any trouble.

The composition of this high-quality paper is as shown below.

Hardwood kraft pulp (LBKP) 80 parts by weight ffi Softwood kraft pulp (NBKP) 20 parts by weight Band of sulfate 1 part by weight Talc
5 parts by weight sizing agent
0.5 parts by weight freeness
400cc Comparative Example In the above example, a roll having a ceramic layer (3) made only of gray alumina without being coated with epoxy resin was used under the same usage conditions as in Example 1 above, and a press roll for a paper machine made of the same high-quality paper was used. When I used it as a roll, the paper stuck to the roll, making it unusable.

The surface roughness of the roll of this comparative example (JISB 06
01) was 3.0 to 5.0 μm (Ra).

Effects of the Invention As described above, the press roll for a paper machine according to the present invention is provided with a base layer made of a metal material having a coefficient of thermal expansion smaller than that of the metal material constituting the core, on the outer periphery of the metal core, A ceramic layer is provided around the outer periphery of this base layer,
Since the gaps between the ceramic particles in at least the surface layer of the ceramic layer are filled with an organic polymer material having mold releasability made of synthetic resin or wax, it can be used in place of conventional stone rolls. Since the roll surface has improved smoothness and there are no voids on the surface of the ceramic layer, the release properties of the wet paper are improved, and the wet paper does not stick to the paper and can be released stably. .

In addition, even after long-term use, it is difficult for pitch to adhere to the wet paper, and a mirror-like finish is possible to give smoothness to the wet paper after pressing, and it is difficult to wear due to the doctor blade used to remove paper waste. It has surface hardness and roll strength that can withstand high loads and high speed rotation for a long period of time, and the roll surface characteristics are homogeneous and it is easy to set the surface characteristics and manufacture. be effective.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic front view of a press roll for a paper machine according to the present invention, FIG. 2 is an enlarged sectional view of section A in FIG. 1, and FIG. 3 is an enlarged sectional view of section A in FIG. FIG. (1)... Press roll for paper machine, (2)... Core body, (3)... Ceramic layer, (4)... Base layer,
(5) Ceramic particles, Synthetic resin layer. Above Figure 1 Figure 2

Claims (3)

[Claims] (1) A base layer made of a metal material having a coefficient of thermal expansion smaller than that of the constituent metal materials of the core is provided on the outer periphery of the metal core, a ceramic layer is provided on the outer periphery of this base layer, and a ceramic layer is provided on the outer periphery of the base layer. A press roll for a paper machine, in which gaps between ceramic particles in at least a surface layer portion are filled with an organic polymeric substance having mold releasability made of synthetic resin or wax. (2) The organic polymer substance with mold releasability that is filled in the gaps between the ceramic particles of the ceramic layer is selected from the group consisting of epoxy resin, phenol resin, polyurethane resin, silicone resin, fluorine resin, and wax. The press roll for a paper machine according to claim 1, wherein the press roll is made of synthetic resin or wax. (3) The surface of the ceramic layer has a surface roughness of 0.2 to 2.
The press roll for a paper machine according to claim 1, which is treated to have an Ra of 0 μm.