Classifications

• • 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
• • 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
  • D21H17/61—Bitumen
• • 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
  • D21H17/62—Rosin; Derivatives thereof
• • 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
• • 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp

Definitions

• My present invention is concerned with the manufacture of fibrous compositions and articles containing organic binders and mineral or other fillers, wherein the fiber distribution and construction is characteristically that of a paper mill product, and is more particularly related to the preparation of a watery pulp in which fiber, binder and filler are intimately associated.
• my invention I employ a basic principle which was set forth in United States Patent No. 1,771,150, of July 22, 1930.
• This principle applies to the manufacture of pulps suitable for formation on a screen by a method which comprises first pre-associating a binder substance and a fibrous material while the fibers are not in water suspension in the sense of constituting a pulp, and after such pre-association has been produced, then suspending the fibrous material and the associated binder substance in water sufiicient to act as a circulating medium, and refining the stock for felting.
• Wit vegetable fibers may be combined various percentages of animal fibers, such as wool, or of mineral fibers, such as asbestos.
• the object of my invention is the production of a pulp of feltable fibers in suspension in a circulating medium with which a binder substance is associated, together with a filler substance.
• Another object of my invention is the production of a novel type of association between theseveral substances which go to make up my pulp.
• Still another object of'my invention is the I provision of a new and useful process for the employment of fillers in pulps which contain binder substances. Still another object of my invention is the production in felted articles of enhanced qualities derived in part from the physical association of the 'ingredients which go to make up the pulp. These and other objects of my invention which will be set .forth hereinafter, or will required of the finand many kinds. I of synthetic resins can be employed. The. be thermo-plastic 50 My present process permits of the use of be apparent to one skilled in the art upon 100 as a one-sta e creosol-forma readmg' these specifications, I accomplish by that certain process and series of manipulations, and in that product of which I shall now describe an exemplary embodiment.
• the synthetic resins 'fier in point of time and temperature for conversion under heat into their infusible and/or insoluble form are requlred when elevated temperatures are employed in the process of drying the resinous gulp product, as, for example, in passing s eets over the heated drying drums of a paper machine.
• Combinations of these various synthetic resins in a felted fibrous structure I can be converted under heat and pressure into dense, so-called laminated phenolic products posessing great tensile strengt-h, desirable electrical properties, resistance to moisture, and to the action 'of organic solvents and dilute acids.
• the base stock for laminated phenolic products has been made by saturating special papers, generally kraft or an absorbent cotton or purified wood cellulose paper, b passing it through a resin solution. The solvent is then evaporated by means of heat, leaving the resinous matter coated upon and partially incorporated in the paper. From the apers so treated the various laminated pro nets of this industry have been made by stackingrtogether either sheets or shapes out there om to make a roduct of the desired thickness and cured tween steam-heated platens in a hydraulic press at temperatures ranging from to 200 centigrade, and under pressures of 1000 to 3000 pounds per square inch.
• the present invention is concerned with a new method for securing a felted fibrous structure containing resin.
• the product can be cured and pressed in equipment, and by the procedure now followed in the handling of paper sheets coated and partially saturated with resin.
• the roduct is quite novel, as will be understood om what follows.
• the method consists essentially ing together in a suitable mixer a mass of wetted cellulosic fibers and. a liquid or semi liquid resin, referabl reduced to this state by means of eat.
• a suitable mixer a mass of wetted cellulosic fibers and. a liquid or semi liquid resin, referabl reduced to this state by means of eat.
• the cellulosic material generallyK paper or a pul has been sufliciently bro en, that is, de brated, .by the action takin place in the mixer, and the resin binderiasbeen uniformly incortprorated or distributed throughout the wet brous mass, more water is added.
• compositions of this character filler substances which are of non-fibrous or substantially non-fibrous character.
• a result of certain character may be obtained by mixing mineral fillers or the like with the pulp as it is being beaten or refined, as by adding suchfillers to the paper mill beater.
• This has its disadvantages, however, residing primarily in that filler substance added to the beater is not homogeneously distributed throughout the body of the pulp, and insofar as it is brought into suspension therein, does not exhibit to any practical extent a stability of association therewith. It is therefore incompletely retained upon the screen when the fibers are felted together to form the finished product. As a consequence, much of it is lost, and the final product becomes nonuniform and may have a distinctly striated character.
• my filler usually substantiallg
• the binder has the same relationship to .the fibrous material in the finished pulp as hitherto, namely, it exists in minute, uncoated particles in stable relationship with the fibers; but it differs from binders hitherto employed by me in that it contains within its body and within the bod of such particles as now constitute the bin er, a substantial quantity of a mineral or other non-fibrous filler. In this way the filler is uniformly distributed, and is in a substantial degree adhesively associated with the binder, whereby, when the pulp is finally formed up, the filler material is very well retained therein.
• the filler need not be added ry to the binder material, but may be added wet if desired, and the mixing continued to the point of driving out the greater part if not all of the water, prior to the addition of the fibrous material.
• the water should be driven out when following 'my preferred procedure, at least to the extent of bringing about an adhesive association between the filler and the binder.
• the relationship of the filler to the binder is preferably that of a completely coated condition of the filler which is' not thereafter alleviated.
• Webs of fibrous material such as paper or the like, which have been coated and/or saturated with a synthetic resin, may be pressed and cured, but they do not exhibit to any markeddegree the properties ofplastic flow under heat and pressure. If any substantial deformation is attempted, the web puckers or ruptures, and the desired result is not perfectly obtained.
• premixed pulps if the binder is inexcess of the fibrous material, the quality of true plastic flow has been noted; but where the binder'is relatively low in amounts, this property has not been perfectly developed.
• thefiller serves to ubna cate the m permittin a certain degree of flow in the bers and a so facilitating the 3 flow of the resin.
• My process is, of course, of especial importance in the field of molded compos1- tions containing synthetic resins, because here it is advantageous for a number of reasons, not the least of which is economic, to kee the amount of binder relatively low, an to secure the mechanical reinforcement of a felted fiber structure.
• the range and u utility of products which can be molded from sheeted fibrous stock containing synthetic resins has been greatly extended by my invention.
• An exemplary resin suitable for my process may be prepared as follows:
• the rate of curing of the resin is determined by'a hot plate test conducted as fol- 65 lows: A small amount of the resin is worked imately 90 seconds, and becomes rubbery in.
• the type of resin used is dependent upon the time and temperature used in drying the finished aper or board and the resin just described is an example of a resin suitable for use in heavy board which is to be dried in a Coe dryer or other apparatus which maintains atem erature between 100 and 125 0., under whic condition the board becomes dry in approximately 2 hours.
• This resinous material is placed in a. suit able mixing or kneading machine, such as the well-known Werner-Pfleiderer mixer, and under the influence of heat is brought to a semi-liquid or plastic condition.
• a. suit able mixing or kneading machine such as the well-known Werner-Pfleiderer mixer
• the desired quantity of'mineral or other filler say slate dust to the amount of 20% by weight of the synthetic resin, is added thereto.
• the filler may be added wet or dry The rotation of.
• the mixer blades is started, and in either instance mixing is carried preferably to the point of forming a homogeneous distribution of the filler material in the binder. If the filler material has been added wet, it is advantageous to continue the mixing until the moisture has been driven out, and until the filler is not only com letely incorporated in the body of the binder, but also in adhesive contact relationship therewith in all its parts.
• the filler will preferably be in a completely coated condition.
• the fibrous material can be readily molded, as hereinabove described, a quantity of fiber can be used such which has been previously wetted with that the resulting pulp will have use 01- lowing composition when computed upon the air-dry basis:
• a suitable fiber furnish is one comprising equal weights (air-dry basis) of rag half stock and sulfite clippings.
• the use of some rial have been thoroughly mixed, but preferably before the water has been driven out of the mass under the influence of heat, and while the fibers have substantially an incompletedly coated condition and an avidity for water, the resultant mass in the mixer is broken down to a semi-pulp by the addition of more water. This semi-pulp may then be transferred to a beater and beaten into a true pulp in which the fibers are fitted for felting, and are suspended in a quantity of water sufiicient to act as a circulating medium.
• This pulp may be refined and/or diluted as desired, and may be formed up upon the screen of a paper makin machine or other pulp forming device. n it the binder exists in minute, uncoated particles in stable and partial adhesive contact association with the fibers, with the binder particles themselves substantially containing the filler materials.
• the formed and dried pulp will have the characteristics,under heat, of plastic flow, and can be formed up under heat and pressure and cured to cause the resin to assume an infusible and/or insoluble condition.
• the resin Prior to the treatment under heat and pressure, the resin should be largely in a secondary or incompletely cured condition, and any scrap which is the result of trimming or cutting the blanks forthe pressing or molding operation, may be re-used in subsequent batches of stock, preferably introduced at the premixing stage, or it can be shredded and used as a molding compound.
• the primary object in adding a mineral' filler to a composition of synthetic resin and a paper making fiber is to secure improved molding properties under heat and pressure for a minimum amount of resin contained therein, the pro er selection of filler and amount thereo is important. While for a given composition this factor can only be determined by experimentation, the use of absorbent materials, such as diatomaceous earths, is not recommended. Materials such as 200 mesh silica, finely ground felds ar and paper makers clay will enerally e found satisfactory. When c0 or is desired the filler may consist in part ofpigments or lakes.
• a pulp of paper making fibers in suspension in a circulating medium containing binder particles in substantially homogeneous distributon, the said binder particles containing filler particles in substantially completely coatedcondition.
• An uncoated composition of felted fibers containin in its interior and within the confines of its surface enough synthetic resin in an incompletely cured stage to flow outwardly upon fusion under heat and pressure so as to form a continuous film wholly encasing the fibers and a mineral filler uniformly distributed throughout said composition and dispersed in said binder.
• An uncoated composition of felted fibers containin in its interior and within the confines of its surface a synthetic resin in an incompletely cured state and a mineral filler, the particles of said filler being coated with and uniformly distributed in the resin material.
• a molding composition comprising a structure of felted fibers and containlng within its confines and in intrafiber distribution a mineral filler associated, as herein described, with a synthetic resin suflicient in quantity to flow outwardly upon fusion under heat and'pressure to form a continuous encasing film.
• a molding composition comprising a structure of felted fibers and containing within its confines and in intrafiber distribution a mineral filler associated, as herein described, with a synthetic resin sufiicient in quantity to flow outwardly upon fusion under heat and pressure to form a continuous encasing'film, and further characterized by the property of plastic flow under the conditions of molding.
• a process of making a pulp which contains a binder and filler material which comprises combining a filler material with the binder substance under conditions permitting an adhesive relationship between said substances, whereby the filler becomes completely coated with said binder, and associating the resulting binder with the fibrous material under conditions in which said fibrous material comes into adhesive contact with said binder material but is incompletely coated thereby, and subsequently dispersing the mass so formed in water to the extent of fitting the fibers therein for formation upon a paper machine screen.
• a process of forming a pulp of fibrous material containing binder and filler substances which comprises associating said binder and said filler substances under saturating conditions, and said binder and said fiber under non-saturating conditions, and subsequently dispersing the mass so formed in water suflicient to act as a circulating medium.
• That process of forming a feltable pulp containing binder and filler substances which comprises dispersing a filler in a binder and subsequently causing the said binder to adhere to fibrous materials in a pulp in water suspension, said binder existing in minute particles in said pulp and containing said filler material in dispersion.
• a process of making fibrous pulps which comprises associating fibers, filler materials, and a binder under conditions insuring a complete coating of said filler material by said binder, but an incomplete coating of said fibrous material by said binder,
• the process of making a pulp of fibrous material, polymerizable binder, and filler material which comprises introducing a polymerizable binder in a secondary or incompletely polymerized stage into a mixing devlce and incorporating therewith a filler material to'the extent of effecting a substantially homgigeneous distribution of said filler in said bin er, afterwards mixing with said mass wetted fibrous materials without completely coating the individual fibers thereof with said binder, adding water and mixin to form a semi-pulp, transferring said semipulp to a heater and beating the said semipulp to form a true pulp of feltable fibers with said binder and said filler in stable association therewith.
• a pulverulent filler and then adding there- 19.
• the process of making a pul of fibrous material, synthetic resin and er which comprises mixing a filler materlal with said resin in an incompletely polymerized stage to the extent of substantial homogeneous distribution, premixing the mass so formed with wetted fibrous material, and beating the resultant product to form a pulp, forming the said pulp upon a screen of a 10 paper machine, drying the formed product, and pol erizing the resin therein under heat an pressure.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Phenolic Resins Or Amino Resins (AREA)
• Paper (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=24104873

Family Applications (1)

Country Status (4)

Cited By (9)

Families Citing this family (2)

• 1931
  • 1931-04-06 US US528248A patent/US1901382A/en not_active Expired - Lifetime
  • 1931-05-16 GB GB14569/31A patent/GB386991A/en not_active Expired
  • 1931-05-21 FR FR717427D patent/FR717427A/fr not_active Expired
  • 1931-05-27 BE BE380116D patent/BE380116A/xx unknown

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