GB2157331A - Impregnated paper and a method for its production - Google Patents

Impregnated paper and a method for its production Download PDF

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Publication number
GB2157331A
GB2157331A GB08508538A GB8508538A GB2157331A GB 2157331 A GB2157331 A GB 2157331A GB 08508538 A GB08508538 A GB 08508538A GB 8508538 A GB8508538 A GB 8508538A GB 2157331 A GB2157331 A GB 2157331A
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GB
United Kingdom
Prior art keywords
impregnated paper
carbonate
paper
condensate
carbon dioxide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08508538A
Other versions
GB2157331B (en
Inventor
Mats Inge
Carl E Johannson
Ulf Kittilsen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Casco AB
Original Assignee
Casco AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Casco AB filed Critical Casco AB
Publication of GB2157331A publication Critical patent/GB2157331A/en
Application granted granted Critical
Publication of GB2157331B publication Critical patent/GB2157331B/en
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/08—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/24—Acids; Salts thereof
    • C08K3/26—Carbonates; Bicarbonates
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/47—Condensation polymers of aldehydes or ketones
    • D21H17/48—Condensation polymers of aldehydes or ketones with phenols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2361/00—Characterised by the use of condensation polymers of aldehydes or ketones; Derivatives of such polymers
    • C08J2361/04—Condensation polymers of aldehydes or ketones with phenols only
    • C08J2361/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Laminated Bodies (AREA)
  • Paper (AREA)
  • Reinforced Plastic Materials (AREA)

Abstract

The paper contains a pre-condensate phenolic resin in which free carbon dioxide-containing bubbles are present and is manufactured by impregnating a paper with an aqueous impregnating solution of a phenol/formaldehyde pre-condensate containing a carbonate, followed by drying and partial curing of said pre-condensate under conditions which result in release of carbon dioxide containing bubbles. The paper may be laminated to plywood by hot pressing to complete curing of the resin. The carbon dioxide provides a combination of long shelf-life for the impregnated paper and rapid completion of the curing.

Description

SPECIFICATION Impregnated paper and a method for its production The present invention relates to a paper impregnated with a pre-condensate of phenol and formaldehyde and to a method for its production Paper impregnated with phenolic resin is manufactured by impregnating a paper web with an aqueous solution of a pre-condensate of phenol and formaldehyde and the web is subsequently dried under heat whereby a certain further curing of the resin to a non-sticky state occurs. The resin in the dry paper web can still melt and it can be finally cured by heating.
The most common use of the impregnated paper is for surface coating of other materials whereby one or several sheets of the impregnated paper is applied using pressure and heat. The resin melts at this and wets the substrate and the resin will then bind by final curing to an unmeltable and insoluble state.
Both at the production of the impregnated paper web and at the final lamination process it is desirable to have a rapid curing of the resin for optimum utilization of machines and presses. The speed can be influenced by selection of resin, by adjustment of pH and by different additives. The curing rate of the resin is hereby generally influenced uniformly in all curing phases. As the impregnated paper generally is used as a semi-finished product with a considerable storage period between the manufacture and the final use an increase of the curing rate can normally only be achieved at the cost of an impaired storage stability. A further problem is that the impregnated paper as a semi-finished product must have good mechanical strength, good flexibility and stable reactivity.Optional accelerators and curing agents which in other situations can be used at direct final curing of phenolic resins can thus not, as such be used for impregnated paper.
The main object of the present invention is to make it possible to increase the curing rate without reducing the storage stability to a corresponding degree. It is a further object of the invention to make it possible to increase the curing rate without impairing the properties of the impregnated paper in other respects.
According to the invention there is provided an impregnated paper containing a phenol/ formaldehyde pre-condensate and bubbles of free carbon dioxide. The bubbles are captured in the dried and partially cured pre-condensate in the paper. The bubbles can be formed during the impregnation and/or drying process due to reaction or decomposition of carbonate which is added preferably to the impregnation solution containing the pre-condensate prior to the impregnation of the paper. Carbonate can also be formed in situ in the impregnation solution by addition of carbon dioxide gas.
It has been found that with an impregnated paper of the invention, containing bubbles of free carbon dioxide, a considerably reduction of press times at lamination is obtained without impairing the storage stability for the impregnated paper. The properties of the paper are not negatively influenced in other respects. On the contrary it has been found that the release of carbon dioxide bubbles in the film gives a film with a high degree of workability.
Suitable carbonates which can be used according to the invention are for instance sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, magnesium carbonate and zinc carbonate. A bicarbonate and particulare sodium bicarbonate is preferred.
The carbonate can be added in an amount of 0,1 to 10 per cent by weight calculated on the pre-condensate, preferably in an amount of 0,5 to 5 per cent.
According to an embodiment of the invention the impregnated paper contains a substantial amount of carbonate which has not been decomposed into carbon dioxide. The amount of undecomposed carbonate in the impregnated paper can be regulated by the selection of carbonate, the amount of carbonate added, the pH of the impregnation solution and the drying temperature.
The presence of carbonate will also increase the curing rate of the phenolic resin. However, it has been found that the formation of bubbles containing carbon dioxide in the impregnated paper is essential for the storage stability of the impregnated paper as a semifinished product.
Conventional phenolic resins or phenol-modified resins for impregnation of paper can be used according to the invention, eg resins having a molar ratio formaldehyde/phenol of about 1,0 to 3,0.
The impregnation solution is preferably in the form of an aqueous solution of the resin, containing about 40 to 80 per cent by weight of the resin.
In manufacturing the impregnated paper according to the method of the invention the carbonate is suitably added to the impregnation solution containing the resin. This can be carried out by bubbling carbon dioxide gas through the solution or by adding a substance which releases carbon dioxide on heating.
Solid carbonates can also be added directly to the impregnation solution or be added in the form of solutions or aqueous slurries. It is particularly preferred to add carbonates which are able to release carbon dioxide during the drying, either by decomposition of the carbonate as such or by reaction with another substance. Soluble carbonates are preferred.
Bicarbonates, such as sodium bicarbonate, have been found particularly suitable. Conventional additives such as release agents, waxes, wetting agents etc can also be present.
After impregnation of the paper web this is dried in conventional manner by heating in air at temperatures between about 1 50 and 200"C. Using the additive according to the invention the drying time can usually be reduced as the resins are cured more rapidly to the desired degree of pre-curing. The conditions at the drying are preferably selected to give a release of carbon dioxide from the carbonate and this can be established by the film becoming more opaque than otherwise.
In addition to selection of carbonate, the pH of the impregnating solution and the drying temperature can be used for influencing the liberation of gas.
After optional intermediate storage in conventional manner the dried paper can be used in conventional applications. Lamination to other materials and/or of several paper layers mutually is normally carried out in presses at pressures between 5 and 20 kp/cm2 and temperatures between 90 and 1 80 C. As has been mentioned, the required time to final curing of the resin can be reduced by means of the invention, often to about half the time.
Depending on the conditions, the press times can for example be between 20 seconds and 15 minutes.
A preferred use for the paper according to the invention is as surface finishing film for wood based materials and particularly as form panel film.
Example To a conventional aqueous impregnation solution for paper containing 60 per cent by weight of a phenolic resin (molar ratio formaldehyde/phenol 1,6; viscosity 1 20 mPas at 25"C), with the pH adjusted to 9,5 in advance, 1 per cent by weight of sodium bicarbonate is added calculated on the impregnation solution. Further, colorants, wetting agents and release agents are added in a conventional manner. The resin is used for impregnating a 40 g/m2 absorbent kraft paper which is dried in the drying zones of the impregnation apparatus at temperatures of between 160 and 1 80 C to give a storage stable film with a total weight of 120 g/cm2 and a remaining moisture content of 6-8 %.
This film is then pressed onto a substrate of plywood in a hot press at a press temperature of 135"C and a pressure of 1400-1800 kPa.
The press time was only 4 minutes compared with about 7 minutes which is normal.

Claims (10)

1. Impregnated paper containing a precondensate of phenol and formaldehyde, characterized in that it contains bubbles of free carbon dioxide.
2. Impregnated paper according to claim 1, characterized in that it comprises an addition of carbonate or carbon dioxide.
3. Impregnated paper according to claim 2, characterized in that the carbonate is a bicarbonate.
4. Impregnated paper according to claim 2, characterized in that the carbonate is sodium bicarbonate.
5. Impregnated paper according to claim 2, 3 or 4, characterized in that the amount of added carbonate is from 0.1 to 10 per cent by weight calculated on the pre-condensate.
6. Impregnated paper according to claim 5, characterized in that the amount is from 0.5 to 5 per cent by weight calculated on the pre-condensate.
7. A method for the manufacture of impregnated paper containing a pre-condensate of phenol and formaldehyde, by impregnating a paper with an aqueous impregnating solution of a phenol/formaldehyde pre-condensate, followed by drying and partial curing of the pre-condensate, characterized in that a carbonate is added to the impregnating solution and that the drying is carried out under conditions which result in release of bubbles containing carbon dioxide in the paper.
8. A method according to claim 7, characterized in that the carbonate is formed in situ in the impregnating solution by bubbling carbon dioxide through this.
9. Impregnated paper as claimed in claim 1, substantially as described in the foregoing Example.
10. A method for the manufacture of impregnated paper, substantially as described in the foregoing Example.
GB08508538A 1984-04-13 1985-04-02 Impregnated paper and a method for its production Expired GB2157331B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE8402059A SE457966B (en) 1984-04-13 1984-04-13 IMPREGNATED PAPER CONTAINING A PRE-CONDENSATED BETWEEN PHENOL AND FORMAL HYDRADE AND PROCEDURES FOR ITS PREPARATION

Publications (2)

Publication Number Publication Date
GB2157331A true GB2157331A (en) 1985-10-23
GB2157331B GB2157331B (en) 1987-07-01

Family

ID=20355562

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08508538A Expired GB2157331B (en) 1984-04-13 1985-04-02 Impregnated paper and a method for its production

Country Status (4)

Country Link
DE (1) DE3513185A1 (en)
FI (1) FI851423L (en)
GB (1) GB2157331B (en)
SE (1) SE457966B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2219765A (en) * 1988-06-14 1989-12-20 Preseal Laminated boards

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB882296A (en) * 1957-03-14 1961-11-15 Owens Corning Fiberglass Corp A composite foam and mineral product and methods for producing same
GB928901A (en) * 1958-07-19 1963-06-19 British United Shoe Machinery Improvements in or relating to stiffener material
GB949859A (en) * 1961-07-21 1964-02-19 J B Broadley Ltd Process for the production of synthetic leather-like material
GB1069625A (en) * 1962-12-04 1967-05-24 Borden Chemical Company U K Lt Improvements in or relating to the manufacture of synthetic resin articles reinforced with fibrous material
GB1116826A (en) * 1965-07-19 1968-06-12 Billingsfors Langed Ab Improvements in textile substituting material
GB1168778A (en) * 1965-10-21 1969-10-29 Sumitomo Bakelite Co Structural Foamed Products and Method for Production Thereof.

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB882296A (en) * 1957-03-14 1961-11-15 Owens Corning Fiberglass Corp A composite foam and mineral product and methods for producing same
GB928901A (en) * 1958-07-19 1963-06-19 British United Shoe Machinery Improvements in or relating to stiffener material
GB949859A (en) * 1961-07-21 1964-02-19 J B Broadley Ltd Process for the production of synthetic leather-like material
GB1069625A (en) * 1962-12-04 1967-05-24 Borden Chemical Company U K Lt Improvements in or relating to the manufacture of synthetic resin articles reinforced with fibrous material
GB1116826A (en) * 1965-07-19 1968-06-12 Billingsfors Langed Ab Improvements in textile substituting material
GB1168778A (en) * 1965-10-21 1969-10-29 Sumitomo Bakelite Co Structural Foamed Products and Method for Production Thereof.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2219765A (en) * 1988-06-14 1989-12-20 Preseal Laminated boards

Also Published As

Publication number Publication date
SE457966B (en) 1989-02-13
DE3513185A1 (en) 1985-10-17
SE8402059D0 (en) 1984-04-13
GB2157331B (en) 1987-07-01
FI851423L (en) 1985-10-14
DE3513185C2 (en) 1987-06-11
SE8402059L (en) 1985-10-14
FI851423A0 (en) 1985-04-10

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