JPH01172613A - Roll for pressing - Google Patents

Abstract

PURPOSE:To improve the exfoliation performance with paper by pouring the poured material for forming polyisocyanurate resin and forming a nonporous polyisocyanurate group resin layer which possesses a Shore D hardness over a specific value after thermosetting and contains inorganic powder onto the surface of a core body. CONSTITUTION:The poured material for forming polyisocyanurate resin which contains at least 50wt.% aromatic polyisocyanate containing at least 20wt.% polyisocyanate group is poured into a mold, and a nonporous polyisocyanurate group resin layer which possesses Shore D hardness of 75 or more after thermosetting and contains inorganic powder is formed on the surface of a core body. Therefore, the exfoliation performance with paper can be improved, and the physical strength can be increased, and the heatresistance for the heat of a steam box can be improved, and the roughness of the surface of a roll due to the slip-off of the inorganic powder is drastically reduced, and the superior molding part performance can be developed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a press roll that is preferably used as an alternative roll to a papermaking top press roll made of natural stone.

[Conventional technology]

The water passes through the water, where it is pressed and dehydrated. A rubber roll is usually used as the bottom press roll that comes into contact with the felt. 7 Nana's Gress roll has high power
-Since it is added directly to wet paper, the following performance is required.

(1) Good separation from paper.

(2) Capable of withstanding high loads.

(3) The surface must be smooth.

(4) When pressing the wet paper, there should be no deformation and the paper should not be cut.

(5) Good doctor resistance.

(6) Low self-heating.

[Problem that the invention seeks to solve]

7 made of granite called stone roll
Press rolls have good paper release properties, but because they are made of natural materials, there are large variations in material quality, and it takes a lot of effort and time to form the rolls.

In particular, the production deadline for large rolls becomes unstable due to the difficulty in obtaining granite. Additionally, press rolls have the disadvantage of being easily scratched by impact.

As an alternative to this, there is known a roll for papermaking and for papermaking, which is made by mixing stone powder such as silica sand into a hard roll. There is a drawback that the stone powder is insufficiently removed, and the falling off of stone powder is promoted during use, causing roughness on the surface. In order to overcome these drawbacks, Japanese Patent Application Laid-Open No. 50-90704 discloses a press roll made of eixy resin and a press roll made of polyester resin. However, these press rolls have poor adhesion to inorganic powder.

A press roll made of 6-nylon resin has also been disclosed, but in addition to the drawbacks of a press roll made of epoxy resin, it has the disadvantage of poor heat resistance. Furthermore, a press roll made of polyurethane resin was published in JP-A-57-95.
Although it is disclosed in No. 395, in the case of this roll as well,
It has the disadvantage of poor moldability.

The present invention provides a press roll that has excellent heat resistance, has extremely little roughening of the roll surface due to shedding of inorganic powder, and has good moldability.

[Means for solving problems]

The present invention provides a casting material for forming polyisocyanurate resin containing 50 weight or more of aromatic polyisocyanate with a polyisocyanate group content of 20 weight or more. This is a press roll characterized in that a non-porous polyisocyanurate resin layer containing inorganic powder is provided on the surface of a core.

Here, the amount of preisocyanurate resin is 5 to 800% by weight per 100% by weight of irisocyanurate resin.
It is preferable to contain a filler of.

Also, aromatic compounds with an isocyanate group content of 20% by weight or more? Diisocyanate is, for example, tolylene-2,4-
or -2,6-diisocyanate, diphenylmethane-2,4'-also Fi-4,4'-diisocyanate,
naphthylene-1,5-diisocyanate, e-tolylene diisocyanate, anisone diisocyanate, diphenyl ether-4,4'-diisocyanate, m-Also#"ipip-phenylene soocyanate phenylmethane-4# 4't 4'-triyne cyanates, tris(4-incyanatophenyl)thiophosphate, polyphenylpolymethylene preisocyanates of the type obtained by condensation of aniline with formalin and subsequent phosgenation, cargenoimide groups or uretonimine groups as described in German Patent No. 1092007; diphenylmethane diisocyanates that are liquid at room temperature, or urethane bonds, allophanate bonds, amide bonds, urea bonds with an incyanate group content of 20% by weight or more,
Examples include modified aromatic polyisocyanates containing acylurea bonds, biurea bonds, to bonds, incyanurate structures, uretidine dione structures, and the like.

Aromatic diisocyanates can also be used singly or as a mixture of two or more. Among these are commercially readily available aromatic preisocyanates, such as tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate.
- diisocyanates and all mixtures of these isomers, monophenylpolymethylene polyisocyanenites of the type obtained by condensation of aniline with formalin and subsequent phosgenation, diphenylmethane-4,4'-zoisocyanate and diphenylmethane-2,4 '-Diisocyanates and all mixtures of these isomers, liquefied diphenylmethane diisocyanates with an isocyanate group content of 20% by weight or more are particularly suitable.

A casting material for forming a polyisocyanurate resin is a material containing 50% by weight or more of an aromatic preisocyanate, a trimerization catalyst, and optionally a resin and monomer that are soluble in the aromatic polyisocyanate and can be copolymerized. etc.

As the trimerization catalyst, known ones can be used, for example,
Alkali metal salts of carboxylic acids with 2 to 12 carbon atoms (potassium acetate, potassium propionate, potassium 2-ethylhexanoate, sodium benzoate, etc.), alkali metal salts of carboxylic acids with 13 or more carbon atoms (sodium oleate, etc.) , potassium lylphate, etc.), basic substances such as alkali metal salts of weak acids other than carboxylic acids such as sodium ferulate, strong basic substances such as sodium methoxide, benzyltrimethylammonium hydroxide, alkali metal urinary oxides, salicyl Chelate compounds represented by aldehyde and potassium chelate compounds, non-alkali metal salts of carboxylic acids such as calcium naphthenate, lead naphthenate, lead caprylate, etc., patent application No. 12671/1986
Examples include combinations of aziridinyl compounds and tertiary amines and/or aziridinyl compounds and cocatalysts (phenols, epoxy compounds, alkyl carbonates, etc.) as described in No. The above catalysts can be used alone or as a mixture. The blending ratio of the catalyst is appropriately determined depending on the pot lie 7 of the casting material and the strength of the catalyst, but it is usually contained in the casting material in an amount of about 0.1 to 10% by weight.

Copolymerizable resins include, for example, active hydrogen-containing resins (hydroxyl group-containing resins and amine group-containing resins such as polyether polyols, polyether polyols,
-Liquor? Nate? polyol, hydrocarbon long-chain 4-liol, polyether polyamine, etc.), unsaturated polyester resin, diallyl phthalate resin, epoxy resin, etc. In addition, copolymerizable monomers include ethylenically unsaturated bond-bearing compounds (for example, styrene, ?nylstyrene, acrylic esters, methacrylic esters,
Examples include allyl alcohol esters.

In addition, as a method for forming a hard polyisocyanurate resin layer on the core, for example, a casting method is used. There is a method of injecting raw materials and curing them.

Inorganic powders include stone powders such as granite, silica sand, and feldspar. The stone powder contains 5102 or 5102 and Az2o3 as main components. In addition, CaF2,
CaO, MgO, At203, Boo, ZnO1Ti0
2, S 102.5n02, Cu2O, Na2S, 1
202, CabSCub, ZnS, Pb8゜pbz2
．． 5b2s5, B1253, A128%81C%Cu2
Powders containing S, 5nS2, HgS, CuI, AgI, etc. as main components can also be used by taking advantage of their surface properties. Depending on the properties of the inorganic powder, if the roll surface is to be made hydrophilic, a hydrophilic powder is used, and if the roll surface is to be made hydrophobic, a hydrophobic powder is used. Also, hydrophilic,
By mixing hydrophobic powders, it is possible to change the properties of the roll surface depending on the mixing ratio.

The press roll of the present invention preferably includes a core such as an iron rod that passes through the center and is coupled to the roll. This core does not necessarily have to pass through the center of the roll, but may be fixed to both end faces of the roll by suitable fasteners.

[Effect]

According to the press roll according to the present invention, the casting material for forming a polyisocyanurate resin containing 50% by weight or more of an aromatic polyisocyanate with a polyisocyanate group content of 20% by weight or more is cast, and the heating effect is obtained after the casting. A non-porous polyisocyanurate resin layer containing inorganic powder with a Shore D hardness of 75 or more is provided on the surface of the core, so it has excellent peelability from paper, strong physical strength, and heat resistance. Excellent: There is very little roughening of the roll surface due to shedding of the inorganic powder, and good moldability can be exhibited.

〔Example〕

Examples of the present invention will be described below.

Prepare a casting mold whose surface is treated with plastic and has a core passed through it. 10 parts by weight of Desmophene 2020 (polyhexamethylene carbonate diol manufactured by Bayer, hydroxyl value 56.2) was melt-mixed at 60°C to 100 parts by weight of di7-dylmethane-4.4/-isoisocyanate. 150 parts by weight of dry and kept borax powder is added to this mixture, and the mixture is stirred under reduced pressure. Add 0.5 parts by weight of N, N', N') to this mixture! Js(dimethylaminopropyl)hexahydro-8-)riazine was added and mixed with vigorous stirring, followed by defoaming for 1 minute at 5 mHg or less in a vacuum desiccator. This material was poured into the casting mold heated to 70°C, and cured at 140°C for 2 hours and at 180°C for 4 hours. After cooling to 140° C., the resulting cured product was taken out from the mold and subjected to surface polishing in a conventional manner to obtain a roll as an example.

COMPARATIVE EXAMPLE The following composition was kneaded in an open mill according to a conventional method, and then formed into a sheet using a calender roll. This rubber sheet was wrapped around an iron core with an ebonite layer formed on the surface, tightened with a wrapping cloth and vulcanized, and finally the surface was polished to obtain a roll of a comparative example.

Composition Parts by Weight Natural Rubber 100 Zinc White 5 Fine Sulfur 33 Vulcanization Accelerator 0.6 Evinite Powder 80 Silica Sand Powder 150 The rolls of Examples and Comparative Examples were tested on a Fourdrinier paper machine together with rolls made of granite. When testing,
The example roll, the comparative example roll, and the granite roll were controlled under the following coating conditions. The pulp from which the paper is made consists of 100 ml of hardwood kraft pulp, contains 10% by weight of sizing agent, and is adjusted to pH 4.5 with sulfuric acid. 7 Leeness is 450d,
The scale weighs 8077m.

The example roll, comparative example roll, and granite have an iron core diameter of 30 mm, an outer diameter% of 60 mm, and a length of 260 mm.

A stainless steel doctor knife was connected to the test roll and the paper was made for 10 minutes. As a result, the example roll of the present invention was less scratched by a doctor knife, had good paper releasability, had less paper residue than the comparative example roll, and had the same performance as the granite roll. I had it. There were no problems with the pressure resistance of the Manen roll.

Further, the press roll of the present invention is preferably used as a press roll for papermaking, but is not limited to this, and can also be used as a calendar roll for backing paper, a gloss calendar roll, a play car stack roll, a smooth f roll, and a calendar roll for magnetic tape. It is also used for fabric embossing rolls, pressure fixing rolls for dry copying machines, etc.

〔Effect of the invention〕

As explained above, the press roll according to the present invention has excellent peelability from paper, excellent strength, excellent heat resistance, and very little roughening of the roll surface due to shedding of inorganic powder, and good moldability. It is possible to demonstrate the

Claims (2)

[Claims] (1) A casting material for forming a polyisocyanurate resin containing 50% by weight or more of an aromatic polyisocyanate with a polyisocyanate group content of 20% by weight or more has a Shore D hardness of 75 or more after being heated and cured. A press roll comprising a non-porous polyisocyanurate resin layer containing inorganic powder on the surface of a core. (2) The press according to claim 1, wherein the polyisocyanurate resin contains 5 to 800% by weight of filler based on 100% by weight of the polyisocyanurate resin. Roll for use.