DE1184201B - Papermaking process - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

LIBRARY DESDEUTSCNEN

PATENT OFFICE

Boarding school Class: D 21h

German'KUr 55Ϊ- 16

Number: 1184201:

File number: H 35931 VI b / 55 f

Filing date: 20th Marc 1959

Opened on: December 23, 1964

The present invention relates to a method for making an improved paper, especially a paper with increased porosity and absorbency and more uniform Texture using a crosslinked fabric. . ■. "·. '

For porous absorbent papers the most important properties are porosity and absorbency and uniform texture. Porosity determines the speed with which liquids or gases can be passed through the paper and is of critical importance for filtration purposes. Absorbency governs the speed with which liquids are absorbed by the paper and regulates the production of saturated and impregnated Papers the speed at which paper is made. Both properties, effective filtration ability and uniform absorption of Impregnants require paper of uniform consistency.

Although known different substances at slightly different speeds on the Dutch treatment respond in papermaking, they all behave in a similar way, namely with increasing grinding of the substance, the resulting paper has lower porosity and absorbency, but more uniform texture. Therefore, the papermaker must become one Compromise between a weaker grind to achieve high porosity and a high absorption capacity, and stronger grinding, to achieve a uniform texture, decide.

The object of the invention is to produce a paper with increased porosity and absorption capacity, without sacrificing the uniformity of its constitution.

The invention thus relates to a method for producing paper with increased porosity and absorbency as well as uniform, external texture, cellulose fibers with Crosslinking agents are treated. The method is characterized in that the raw cellulose fibers first made alkaline in a manner known per se, then with organic polyfunctional crosslinking agents such as formaldehyde, polyhalides such as 1,3-dichloroacetone, polyaldehydes such as glyoxal or polyepoxides such as epichlorohydrin are crosslinked, whereupon they are ground in a manner known per se (opened) and processed into paper.

Papermaking process

Applicant: · ■ '.'...

Hercules Powder Company, Wilmington, DeL

(V. St. A.) ^: ■■ '- ■

, Representative: - - - _:

Dr.-Ing. A. van der Werft, patent attorney,
Hamburg-Harburg 1; WilstoTf er Str. 32

Named as inventor: .... ', ..';.
John Arthur Harpham; , · .1 ■:
Harry Willison Tumer _y Wilmington, Del,
, (V.StA.). "-

Claimed priority:

V _: St. v.4i8Sferika from March 31st, 1958 (724817)

In addition to the CeiM'oseiäjierh, which in such a way get networked Molektfie, can also non-crosslinked cellulose soda can be used.

It's basically known 'how networked, for that Cellulose useful for purposes of the present invention by conversion into the polyfunctional Reactants is to be produced. Such however, cross-linked cellulose is: not yet for Manufacture of paper-been used.

It is known to use cellulose fibers; which are to be used in papermaking 'are to be modified in various ways.'; The production of paper of reduced WasSeYabsorption has therefore already been proposed that cellulose fibers have to implement halogen derivatives of ParaffinkönlMwässerstoffen. According to another proposal, cellulose fibers are etherified with benzyl chloride or its homologues. By converting def fibers with certain monofunctional substances, such as B. palmitic anhydride, a paper is to be obtained that has completely lost its ability to absorb water.

According to other proposals, the cellulose fiber used for paper production is not treated, but the finished paper. So is. it is known to add formaldehyde to finished paper. treat. Through treatment of paper with a methylol compound, e.g. B. Tetramethylolacetylennarnstbff, the paper should become waterproof. Such; Treatment of the finished paper can. However, the "according to the invention sought He does not produce his own personality.

409 759/323

cleaned with subsequent bleaching, then washed, spun and dried to yield of 85.6% of the substance. The fabric was transferred into hand-scooped leaves and tested in the manner described above. The associated Values can be found in Tables 1, 2 and 4.

Rather, according to the invention, the cellulose fiber is opened before it is opened and processed into paper is brought to reaction with the polyfunctional crosslinking agents, so that chemical bonds are created within the fiber, from which the process is to be sharply distinguished, in which the chemical bonds are created between the fibers. It is therefore essential to the invention that Crosslinking carried out in the usual papermaking processes prior to the refining treatment so that the type of crosslinking is a chemical bond within the fiber, what is best considered chemical intrafiber connection is to be designated.

The crosslinking is immersed by reacting cellulose with formaldehyde or a reactant 15 room temperature, then spun and with at least two reactive functional groups in vacuo overnight at room temperature causes. The expression »polyfunctional rolls. This treatment was followed by the usual one Reagent «is used here to make mold cleaning as in Examples 1, 8 and 15. The eraldehyde and compounds with at least two held linters were washed, spun functional groups made with cellulose or so and dried to a yield of 84.5% fabric cellulosic substances are reactive to emzu- yield. The fabric was made into hand-scooped leaves

Example 2

Table 1
Rough sample

A 600 g swatch of raw second cut cotton sinter was dissolved in 10 parts of 8% aqueous Sodium hydroxide for 20 minutes at about

conclude. The term "poly" used here means at least two. In addition to Formaldehyde, these reactants include polyhalides, e.g., S-dichloroacetone, polyaldehydes, B. Glyoxal; Polyepoxides such as epichlorohydrin and the like.

The improved paper according to the invention can be clearly seen from the following examples. The specified Percentages are by weight. In all

ter transferred and in the manner described above checked. The associated values can be found in Table 1.

Examples 3 and 16

Tables 1 and 4 Epichlorohydrin An approximately 45 kg sample of raw second cut

Examples were the samples at 2.5%> consistency 30 n cotton ^{lint was divided into 10 parts of 7.7 e} / oigem

and neutral pH in a 600 g Valley Läbor-Hollander produced during 1.5 and 2 hours with a load-bearing plate load of 4.5 to 6 kg depending on from the condition of the Dutch, such as watery sodium hydroxide for 20 minutes immersed at 38 to 43 ° C and spun. The alkali cellulose was in the digester at 35 ° C given and added about 2 kg of epichlorohydrin and

judged by an experiment with a standard substance. 35 circulated the mixture for 1.5 hours while wel-die Samples were made on an 18 kg basis weight rather time the temperature was increased to 110 ° C. (24 x 36 x 500 sheet reams) using a. This treatment was followed by the usual cleaning Noble and Wood hand scooping device as in Examples 1, 8 and 15. The resulting scooped. This way of working required that the forming of the net scoured cloth was made into handmade Sheet from a 0.025% slurry in the mold 40 sheets transferred and as described above

(closed white water system), the wet pressing between felts and the drum drying on the Sieve at about 116 ° C.

Hand-scooped leaves were tested for water absorption (TAPPI standard method T 432 m-45) and air resistance (TAPPI standard method T 460 m-49). These tests actually measure the reciprocal value of the property to be determined. Method T432m-45 measures the time in seconds

checks. The associated values can be found in Tables 1 and 4.

Examples 4, 13 and 17, Tables 1, 3 and 4

Epichlorohydrin

A 600 g swatch of mechanically cleaned raw second cut cotton lint was divided into 10 parts of 8% sodium hydroxide for 20 microns, in which a 0.1 ml drop of water is immersed in the 50 groove at room temperature and then leaf is taken up; the longer that time is to be flung. 93 g of epichlorohydrin were used to reduce the absorption capacity of the leaf. Holding alkali cellulose sprayed and the mixture method T 460 m-49 measures the time in seconds in which 100 cm ^{3 of} air circulated under constant pressure in a vacuum 70 hours at room temperature. This treatment was followed by the usual tearing of 6.45 cm ² of paper; the longer this inclination is by a time, as in Examples 1, 8 and 15, the lower the porosity of the sheet. Yield of 83.0% fabric. The accrued

The uniformity of the handmade samples was visually compared to Control hand samples assessed.

Examples 1, 8 and 15

Tables 1, 2 and 4 control

A 600 g swatch of mechanically cleaned raw second cut cotton lint was made in the Laboratory according to the usual procedure including digestion of alkali under elevated temperature and pressure

Lene reticulated fabric was made into handmade sheets transferred and treated as described above. The associated values can be found in Tables 1, 3 and 4.

Examples 5 and 20 Tables 1 and 4 1,3-dichloroacetone A 600 g swatch of raw second cut cotton sinter was divided into 10 parts 8Voigen aqueous Sodium hydroxide immersed for 20 minutes at room temperature and spun. To the alkali

cellulose were 60 g of 1,3-dichloroacetone in 500 ecm 40% aqueous isopropyl alcohol and the resulting mixture in vacuo for 4 hours circulated at room temperature. After cleaning as described in Examples 1, 8 and 15, the 84% yield of crosslinked! Brought fabric into handmade sheets and as described above checked. The associated values can be found in Tables 1 and 4.

Examples 6 and 12

Tables 1 and 3

control

A 450 g sample of mechanically cleaned raw, second cut cotton lint, which in a technical plant in the same way as the Laboratory cleaning of Examples 1, 8 and 15 were cleaned in hand-scooped sheets

10 transferred and checked in the manner described above. The associated values can be found in Tables 1 and 3.

'^; Example 7 ....

Tabel!
. Epichlorohydrin

A 500 g swatch of mechanically cleaned raw second cut cotton linters which are cut into a manner as in Boispietea 6 and '12 technical had been cleaned, it would be 8% in 10 parts aqueous sodium hydroxide for 20 minutes Immersed in room temperature and then spun. The obtained alkali cellulose was mixed with 25 g of epichlorohydrin sprayed and circulated for 65 hours at room temperature. The product was washed and dried to a yield of 96.8%. to result in cross-linked material. The associated values can be found: is Table 1.

Tabel

example Crosslinking agents
Art Amount in
⁰ zo of fiber Vennahlzeit
in hours water
absorption
in seconds .Air resistance
Sec / tOO cm "
Square inches nature
in comparison
to the control sample 1 throat (cleaned in the laboratory
Control pattern for Bei
games 1 to 5) no 1.5
2.0 59
104 '12
43 2 none (caustic immersed
tes rough sample for Be
games 3 to 5) no 1.5
2.0 57
103 " ^{:: v:} 10
, rn; ^ :: ·.! - 3 Epichlorohyrin 4th ! ' ⁵ 10 ■: ... ·. ·: ■, 2. - more uniform _; 4th Epichlorohydrin 15.5 1.5
2.0 4th
8th -- 0.2
Ö, 8 more uniform
more uniform 5 1,3-dichloroacetone 10; 1.5
2.0 42
57 6th
13th in the same way
uniform
in the same way
uniform 6th none (technically cleaned
Control pattern 'for Bei
game 7) •no 1.5
2.0 61
87 7th
32 - 7th Epichlorohydrin 5 1.5
2.0 7th
14th less than! 1
1.4 ^{5 more} uniform
more uniform

Example 9
Table 2
control

A 600 g swatch of raw second cut cotton sinter was refluxed for a Hour in 15 parts by volume of acetone heated, which 1 percent by weight, based on the fiber, of sulfuric acid contained. After thorough washing with water, the fabric was as in Examples 1, 8 and 15 purified to give a yield of 83.3%. The cleaned fabric was made into handmade sheets transferred and then checked as described above. The associated values can be found in Table 2.

Example 10

Table 2
formaldehyde

The procedure of Example 9 was repeated with the addition of 60 g of formaldehyde to the acidic Acetone linters mixture before boiling, reflux. After washing and cleaning, the incurred 79.5Vn Ausbeujkan crosslinked substance in Hand-scooped leaves are transferred and checked as described above. The associated values are then checked in Table 2.

55

60

Example 11

Table 2
Glyoxyal

The procedure of example. 10 was repeated using 60 g of glyoxyal instead of formaldehyde. After washing and cleaning the incurred 81.5%) yield of crosslinked material. overfilled in nano-scooped leaves and as described above;}, checked. The associated Values can be found in Table 2:. .

Table 2

example Crosslinking agents
Art Amount in
% of the fiber Grinding time water
absorption
in seconds Air resistance
Sec / lWcm »
Square inches . nature
in comparison
to the control sample 8th none (laboratory-cleaned
Control sample) no 1.5
2.0 59
104 12th
43 -. 9 none (raw sample cooked in
acid acetone) no 1.5
2.0 61
88 11
45 10 formaldehyde 10 1.5
2.0 35
76 8th
15th more uniform
more uniform 11 Glyoxal 10 1.5
2.0 48
81 11
16 more uniform
more uniform

Example 14
Table 3

Mixture of crosslinked fiber - non-crosslinked

fiber

A 500 g swatch of mechanically cleaned second cut raw cotton lint was made in 10 parts of 8% aqueous sodium hydroxide during Immersed for 20 minutes at room temperature and then spun. 75 g of epichlorohydrin were sprayed onto the resulting alkali cellulose and the mixture in vacuo for 5 hours at room temperature circulated. This treatment was followed by the lent cleaning as in Examples 1.8 and 15 to to give a yield of 76.0% crosslinked fabric. 0.5 pounds of this crosslinked fabric was used with 0.5 pounds of commercially available purified cotton linters of the type used in Examples 6 and 12 are blended. The mixture of substances obtained was placed in hand-scooped leaves and tested above. The associated values can be found in Table 3.

Table 3 Mixture of crosslinked fiber - uncrosslinked fiber

example Commercially available
cleaned linters
lb Networked linters
lb Grinding time
in hours water
absorption
in seconds Air resistance
Set / 100 cm '
Square inches nature
in comparison
to the control sample 12th
13th
14th 1
no
0.5 no
1
0.5 1.5
2.0
1.5
2.0
1.5
2.0 61
87
4th
8th
15th
36 7th
32
0.2
0.8
2
12th more uniform
more uniform
more uniform
more uniform

Example 18

Table 4
Substitution (glycidol)

A 600 g swatch of mechanically cleaned raw second cut cotton lint was made in Immersed 10 parts of 8% aqueous sodium hydroxide for 20 minutes at room temperature and then hurled. To the alkali cellulose, 92.8 g of glycidol were added and the resulting mixture circulated in vacuo for 4 hours at room temperature. After cleaning according to the examples 1, 8 and 15, the 85.7% yield of substituted fabric was brought into hand-scooped leaves and checked as above. The associated values can be found in Table 4.

Example 19

Table 4
Substitution (a-chlorohydrin)

A 500 g swatch of mechanically cleaned raw second cut cotton lint was placed in 10 parts of 8% aqueous sodium hydroxide

Immersed for 20 minutes at room temperature and then spun. 50 g of chlorohydrin in 50% aqueous solution were sprayed onto the alkali cellulose and the resulting mixture was circulated in vacuo for 21 hours at room temperature. After purification as in Examples 1, 8 and 15, the yield was 77.6% on substituted material brought into hand-scooped leaves qad tested as described above. The corresponding ^ values can be found in table 4. .7

Example 21

Tables
Substitution (chloroacetone) / ■:

A 500 g sample of mechanically cleaned, raw second-cut cotton lint was immersed in 10 parts of 8% aqueous sodium hydroxide for 20 minutes at room temperature and then spun. 50 g of chloroacetone in a 50% aqueous solution were sprayed onto the alkali cellulose and the mixture obtained was circulated in vacuo for 16 hours at room temperature. After cleaning according to Examples 1,

10

8 and 15, the 81.3% yield of substituted fabric was brought into hand-scooped leaves and as above described checked. The associated values can be found in Table 4.

Table 4

Properties of handmade leaves made from chemically modified linters Effect of networking versus substitution

example treatment
Reactants ■
the fiber reaction VermaÜLä5eit
in hours Waaser-
äbSQSpäon
to seconds Air resistance
Sec / 10Ö tan »
Square inch 15th none (laboratory cleaned
Control pattern for the Bei
games 16 to 21) no no 1.5
2.0 59..
104 12th
43 16 Epichlorohydrin 4th Networking 1.5 MJ 2 VCH ₂ -CH-CH ₂ Cl / 17th Epichlorohydrin 15.5 Networking 1.5
2.0 4th
8th 0.2
0.8 18th Glycidol 15.5 substitution 1.5
2.0 38
ίσο 14th
36 VCH ₂ -CH-CH ₂ OH / 19th α-chlorohydrin
(ClCH ₂ - CHOH - CH ₂ OH) 10 substitution 1.5
2.0 56
85 12th
41 20th 1,3-dichloroacetone 10 Networking 1.5
2.0 42
57 6th
13th VClCH ₂ - C - CH ₂ - CH / 21 Chloroacetone
(? ) 10 substitution 1.5
2.0 54
91 12th
58 \ ClH ₂ -C-CH ₃ /

The above examples clearly show that when polyfunctional Reactants used to break down cellulose prior to the refining treatment To cross-link papermaking, paper made from the fabric thus obtained, much more porous and absorbent is as paper made of a material that has not been cross-linked. In some examples the improved paper made according to the invention was 60 times more porous and 15 times more absorbent than usual paper. Furthermore, there will be remarkable improvements in porosity and absorbency obtained without any loss of uniformity in texture and often even in Combination with an increase in uniformity. From the previous examples It can also be seen that the invention is based on the crosslinking of purified (Examples 6 and 7) as well as crude Cotton linters (Examples 2 to 5) is applicable. In addition, these examples demonstrate that the invention can also be used for mixtures of crosslinked and non-crosslinked linters, the here being the The resulting paper reported improvements proportional to the percentage of crosslinked used Linters is. The examples in Table 4 show that the invention is not applicable to monofunctional ones Reactants, because such reactants cause substitution in the cellulose molecule and in the essentially no improvement in absorbency and porosity of that made therefrom Paper (Examples 18, 19 and 21 compared with Example 15), while polyfunctional Reactants cause crosslinking and a substantial increase in absorption capacity and Porosity of the paper produced from the crosslinked material result (Examples 16, 17 and 20 in comparison with example 15). Because the nature of both the networked patterns and the substituted ones Patterns in Table 4 were essentially the same, can be seen on the basis of the nature of the crosslinking cannot be distinguished from substitution and therefore it has not been included in Table 4. Networking examples 16, 17 and 20 in Table 4 are the same as 3, 4 and 5 in Table 1.

Thus it can be seen that the invention resides in the discovery that crosslinked cellulosic fabric can be found in responds to mechanical grinding in a different way, as is the case previously known for papermaking substances used do so that paper made from ground cross-linked! Fabric, one completely different, unexpected and highly desirable combination of such properties as porosity, Has absorbency and uniformity of texture. In particular, the invention enables the production of a paper sheet with greatly increased porosity and absorbency and at the same time with at least as good and often best

«9 759/323

its uniformity of texture. So far there has been no means of achieving high porosity and absorbency without serious loss of uniformity of texture, because with the usual Fabrics porosity and absorbency are reduced by grinding, while uniformity the quality thereby increases.

The paper according to the invention has a number of important uses, including perhaps the two most important filter papers and what are known in the art as absorbent papers. Filter papers are a natural term. To mention a few uses: filter papers are used as oil filters, battery plate separators, air filters and filters in the chemical laboratory. Absorbent papers include wide and varied areas of use, e.g. B. electrical Papers, saturation paper and impregnated papers or paper plastics.

The various common sources of cellulosic material used in the manufacture of paper can be used in the process of the invention, including cotton linters, wood pulp and the like

10

Claims (2)

Patent claims: 1. A process for the production of paper with increased porosity and absorbency as well as uniform external properties, the cellulose fibers being treated with crosslinking agents, characterized in that the raw cellulose fibers are first alkalized in a manner known per se, then with organic polyfunctional crosslinking agents such as formaldehyde, polyhalides such as 1 , 3-dichloroacetone, polyaldehydes such as glyoxal or polyepoxides such as epichlorohydrin are crosslinked, whereupon they are ground (whipped) in a manner known per se and processed into paper. 2. The method according to claim 1, characterized in that that in addition to the cellulose fibers, which contain crosslinked molecules, non-crosslinked cellulosic material is used. Considered publications:
German Patent Nos. 528722, 693209, 372, 752308, 752630, 853 438, 895436, 653, 924185. 409 759/323 12.64 @ Bundesdruckerei Berlin