2 The Relationships between Fibrous Materials and Paper Products. Concepts. Prospects CRISTOFOR I. SIMIONESCU Polytechnic Institute of Jassay, Romania
1. The concept of relationships between "fibrous materials and paper" in the course of the fundamental processes of paper converting and obtainment. Paper characteristics For quite a long time, relations which can be established between pulp, as the original fibrous material, and paper, the end product of a series of intermediate technological processes, have been the intuitive concern of paper producers. Yet the detection of qualitative and especially quantitative relations apt to outline the reciprocal influences between the original properties of the cellulose fibrous material and those of the paper end product (physical, Theological, mechanical strength paper properties) is a matter of future achievement. In the course of paper-converting a series of operations and processes (which are sketched out in figure 1) come between pulp (the raw material) and paper (the end product). Modern technologies c a l l for an additional use of auxiliary (non-fibrous) materials having specific functions. The use of adhesives leads to a reevaluation of the above mentioned sketch of influences and thus we get a completed form (figure 2). From figure 2 we may infer that pulp is l i k e l y to be influenced by an addition of adhesives which, in their turn, exert an influence on the fundamental operations. However pulp has a decisive part in lending paper certain specific characteristics. Similar decisive actions are brought forth by a number of adhesives. 39
40
CELLULOSE
FAC
PULP ^
Q_ _l
A
LL
Ζ
which determines the degree of s i z i n g , the r e t e n t i o n of the f i l l i n g m a t e r i a l , the dyeing capacity, the forming and dewatering of the sheet on the paper machine. The studies bear evidence ( 3 . 4 ) of a greater 5 p o t e n t i a l i n reed (-9 mV) and straw ( - 8 , 5 mV) pulp, as compared to bleached spruce f i r pulp (-6 m\0 . This explains the d i f f e r i n g behaviour during the paper s i z i n g process i n point of c o l l o i d a l i n s t a b i l i z a t i o n which takes longer i n reed and straw pulps than i n spruce f i r pulp. Thus the degrees of paper s i z i n g observe the f o l l o w i n g order: reed pulp
• > • •— Water NaOH Alcohol 10% ethylic
Table
5
53.53
47.03 28.77
22.37
Cellulose Lignin
8.25
17.11
Pentosans
1.86
2.1
Cellulose/ lignin ratio
%2 ~ beating degree of beech pulp, °SR
x^ - beech pulp, %
χ
- 0.00005 X o
2
χ
n
9
- O.OOOOlx + 0.00067 x x
g
+0.00043 χ χ + 0.00373 x
Opacity a f t e r calendering
χ
χ
y » 0.77 + 0.00151 χ
Tearing r e s i s t e n c e , g
2
χ
χ
Burst strength i n dry s t a t e , Kgf/cm
0
Regression equations ^ y = 4200 - 43 χ + 40 x y = 4.73 - 0.072 χ + 0.00017 χ y = 78.7 - 0.196 χ
Breaking length, m
Λ
c h a r a c t e r i s« +t4i c«s
C o r r e l a t i o n equations of strength p r o p e r t i e s of paper obtained with short f i b e r s pulp
0.34
%
Ash
Beech
Species
4
Chemical composition of beech and spruce
Table
2.
Fibrous Materials and Paper Products
SIMIONESCU
0
25 50 75 100 BEECH PULP
53
Figure 12. Variation of the waterproofing characteristics of the preconsolidated paper varie ties with beech pulp mixed with unbleached spruce fir pulps. Beating degree of the two pulps is 40° SR, with an addition of 3% colophony glue and 1% PPE resin.
0A80 (U60 £(K40 δ 0.420
60°SR 48°SR 40°SR 31°SR 20°SR 29 50 71 100 BEECH PULP [%]
£0.400 CL
g 0.380 ο 0.360
Figure 13. Variation of the compressi bility of preconsolidated papers vs. the variation of the bleached beech pulp addition and of the beating degree of softwood, with an addition of 3% colo phony glue 1% PPE resin, and 12.5% kaolin y
Figure 14. Variation of superficial con ductivity and zetha-potential vs. PPE con tent zetha-potential. (O) Unbeaten pulp, (Φ) beaten pulp; superficial conductivity (X) unbeaten pulp, (—) beaten pulp.
54
CELLULOSE AND-FIBER SCIENCE
£ 7000t
g 4000> x3000-
Q5
1.0
2.0
% PPE
3.0
Figure 15. Strength variation of dry papers obtained from (a) unbeaten and (b) beaten bleached softwood sulfate pulps, with an addition of PPE resin
2500 r 22502000•1750 r H1500E
§ i o o o -
* 750-
(/>
t
h 500fi
OLu-
Q5
1.0
2.0
%.PPE
3.0
Figure 16. Strength variation of wet papers obtained from (a) unbeaten and (b) beaten ground bleached softwood sulfate pulps with an addition of PPE resin
2.
siMiONESCu
Fibrous Materials and Paper Products
55
1.0-
I I I I I I I I ». 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 PPE,%
ο J
*0
Figure 17. Dimensional variation of two types of paper with the amount of added PPE resin. (1) Di mensional variation of type 1 under the influence of a 2% melamine addition; (2) dimensional varia tion of type 1 with the addition of PPE resin; (3) dimensional variation of type 2 under the influence of a 5% melamine addition; (4) size variation of type 2 with the addition of PPE resin.
2
\.,PPE
a
°
Figure 18. Suspension breaking length variation vs. the addition of PPE resin and consistence in bleached sulfate pulps from unbeaten softwood materials
CELLULOSE AND FIBER SCIENCE
56
A s i m i l a r v a r i a t i o n takes place i n dry and wet r e s i s t a n c e s and dimensional s t a b i l i t y as can be seen i n f i g u r e 19. The changes c i t e d above may be accounted f o f by the p e c u l i a r T h e o l o g i c a l behaviour of the f i b r o u s suspension i n the r e g i o n of the i s o e l e c t r i c point, which ensures optimum conditions f o r the paper f o r mation* Operations such as s i z i n g , short f i b r o u s materials r e t e n t i o n , f i l l i n g materials r e t e n t i o n and even dewatering on the paper-machine are also l a r g e l y i n fluenced by introducing PPE adhesive i n t o the paste(1S)« A maximum degree of s i z i n g i s achieved with an a d d i t i o n of only 1 percent PPE r e s i n , when using 3 percent aluminium sulphate, i . e . 80 percent l e s s than i n case of the output i n usual processing. The papers thus obtained have a pH tending to the n e u t r a l value (6,5) and physical-mechanical p r o p e r t i e s s i m i l a r to those r e s u l t i n g from the c l a s s i c a l r e c e p t i o n (14* 2021). Figure 20 shows the described v a r i a t i o n s . As regards the recorded e f f e c t s upon f i l l i n g materials r e t e n t i o n and short f i b r e s r e t e n t i o n , they are to be found i n f i g u r e s 21 and 22. The study of vallum papers, processed i n the presence of the PPE adhesive, r e s u l t e d i n the f o l l o w ing c o r r e l a t i n g equations: F(%) = 0.5
3(mV) = 0.12
0.5 χ
+ 0.73 x
χ
0.03 χ 0.105
2 χ
- 0.442 x x 2
2
+ 1·383 χ
- 0.725 x
+ 0.116 x ^
2
- 1.25 x| - l . l x
+ 0.934 x
χ
χ
5
2 2
?
-
- 0.011 x
+ 0.262 x ^
(1)
5
2 ?
+
-
5
(2)
where the dependent v a r i a b l e s are: F - fibrous material retention y i e l d J - zetha e l e c t r o k i n e t i c p o t e n t i a l of the suspension The independent
v a r i a b l e s are the f o l l o w i n g :
x ^ colophony glue a d d i t i o n x - aluminium sulphate a d d i t i o n x*- PPE r e s i n a d d i t i o n 2
2.
siMiONEScu
Fibrous Materials and Paper Products
57
ε
CL
3θηΙ—«-J—ι—ι—ι ^ 0 1.0 J U
1 2.0
J
3.0 Ρ Ρ Ε , %
Figure 19. Suspension breaking length variation vs. the addition of PPE resin and consistence in bleached sulfate pulps from beaten softwood materials
100-
Figure 20. pH of the environment and the sizing degree of the papers obtained with 3% colophony glue with and/or with out an addition of 1% PPE resin and rising quantities of aluminum sulfate or natrium aluminate + aluminum sulfate. Degree of sizing: (O) 5% aluminum sulfate; (Φ) 1% PPE + 1% Al (SO ) ; ((D) 1% PPE + 1% aluminum sulfate + natrium aluminate. pH: (X) 5% aluminum sulfate; (-{-) 1% PPE + I % aluminum sulfate. 2
%Al2(SO^) .18H 0 3
2
k s
58
CELLULOSE AND FIBER SCIENCE
Figure 21. Retention yield variation of the calcium carbonate with PPE resin addition in the case of bleached sulfate pulp which has been beaten for 35 min with an initial addition of 1-10% fillings; 2-20% fill ings; 3-5% fillings
6Θ-
%,PPE
Figure 22. Variation of the titanium dioxide with PPE resin addition retention yield, in the case of bleached sulfate softwood pulp which has been beaten for 35 min in a Jokro mill, with an initial addition of 1-20%fillings;2-10%fillings;3-5% fillings
2.
siMiONESCu
Fibrous Materials and Paper Products
59
The l a s t values have the f o l l o w i n g l i m i t s : s
x^ = 0-3 percent; x 0 - 8 percent; x^=0-1.2 percent 2
In the s p e c i f i c case when i n equation (1) we use 3 percent colophony glue ( x = +1.682) and 4 percent of aluminium sulphate (x - 0 ) , we obtain equation (3): 1
0
d
F » 95.84 + 0.73 x
- 1.1 x
?
2
(3)
The r e l a t i o n describes a curve having a maximum when F = 95.97 percent, corresponding to a quantity of 0.718 percent PPE r e s i n (x^ = +0.332). The y i e l d increase regarding the f i b r o u s m a t e r i a l r e t e n t i o n i s F = 9.1 percent. Under s i m i l a r c o n d i t i o n s , we get equation (4)
3
2
-0.23 + 1.82 x - 0.011 x (4) where from we f i n d the f o l l o w i n g value J = +0.37 mV, f o r which the y i e l d i s at i t s highest (region o f the isoelectric point). S i m i l a r l y i n f l u e n c i n g f a c t o r s of the PPE a d d i t i o n i n the stock dewatering process on the newspapermachine have been determined. The f o l l o w i n g c o r r e l a t ing equations have been used: s
3
?
1
Κ (cm s*" ) = 9.1 - 1.18 χ - 0.42 χ
2
- 0.32 x
χ
1
(Hcrn^ )
2
+ 0.322 x
χ
- 0.294 x ^
2
= 2.87 + 0.273 χ
χ
- 0.1 x + 0.04 x-j + 0.05 x + 0.0146 XjXg 5
- 0.203 χ - 0.43 x
2 χ
2 3
- 0.763 x
2 2
- 0.092 x ^
2 3
+ 2.28
2
(5)
+ 0.0167 x
2
J (mV) = 1.18 + 0.885 x
-
?
-
2
+ (6) -
- 0.763 x
2
-
2
- 0.705 χ χ 2
?
(7)
As dependent v a r i a b l e s the f o l l o w i n g have been assumed: Κ - f i l t e r i n g rate / (> 'c ΟC Ε %
73
determining influences
PAPER
determining influences
Figure 23. Diagram of the fibrous materiaV-operations-additives-paper product interrelations
Figure 24
SCIENCE
2.
siMiONEScu
Fibrous Materials and Paper Products
69
The diagram provides the p o s s i b i l i t y of systematica l l y exploring the interferences of the three i n fluencing factors. The concern with using mixtures of chemical and pulp f i b r e s o r i g i n a t e d f i r s t l y i n the l i m i t e d performances of t r a d i t i o n a l paper i n some of i t s uses and secondly i n the high cost of synthetic paper obtained from chemical f i b r e s 100 percent* A compet i t i v e evolution of the two types may be foreseen. Economical reasons and improvement of e x i s t i n g technologies w i l l exert a great influence on t h i s evolution. Conclusions The i n t e r r e l a t i o n s of f i b r o u s material-paper product have been c o n s i s t e n t l y c h a r a c t e r i z e d . The leading general concept asserts the i n t e r ference of moderate influences or of determining actions r e s u l t i n g from the fundamental operations and the a d d i t i o n of a d d i t i v e s , between the properties of the i n i t i a l f i b r o u s material and those of the f i n a l paper product. The i n v e s t i g a t i o n has been d i r e c t e d towards the f i b r o u s material-additives-fundamental operations-paper c h a r a c t e r i s t i c s system i n the case of short f i b r e s from annual plants pulp (reed, straw) and hardwoods. Q u a l i t a t i v e c o r r e l a t i o n s has been determined i n the f i r s t place and afterwards quantit a t i v e i n t e r p r e t a t i o n has been given to them. Some r e l a t i o n s proved apt f o r being introduced into a mathematic model, the i n f l u e n c i n g f a c t o r s enabling the optimization of paper c h a r a c t e r i s t i c s or of the fundamental operations. The determining influence of a d d i t i v e s has been i l l u s t r a t e d by use of the c a t i o n - a c t i v e PPE r e s i n . The r e s i n modifies e s s e n t i a l l y some fundamental operations and has a d i r e c t e f f e c t on improving paper properties. S i m i l a r i n t e r r e l a t i o n s have been determined i n the case of a r t i f i c i a l and synthetic polymers introduce ced i n the composition of the pulp f i b r o u s m a t e r i a l . The e f f e c t s are due to the symbiosis between the properties of the paper properties of the synthetic polymers and of the n a t u r a l pulp.
70
CELLULOSE AND FIBER SCIENCE Literature
1 Cr. Simionescu, Gh. Rozmarin, Chimia stufului, Ed. Tehnică, Bucureşti, 1966. 2 Cr. Simionescu et all, Zellstoff und Papier, 1963, 12, 327. 3 E. Poppel, S. Petrovan, Cr. Simionescu, Buletinul Inst. politehnic Iaşi, 10 (14), 1-2, 155 (1964). 4 Cr. Simionescu, Gh. Rozmarin, Chimia lemnului şi a celulozei, v o l . I , Litografia I . P . I a ş i , 1972. 5 V. Diaconescu, E. Poppel, P. Obrocea, Buletinul I.P. I a ş i , 9(13), 3-4, 155 (1963). 6 V. Diaconescu, E . Poppel, P. Obrocea, Celluloză
şi Hîrtie, 12, 5-6, 184(1963). 7 Cr. Simionescu, M. G r i g o r a ş , A. Cernătescu-Asandei Chimia lemnului din RPR, Ed. Academiei R.P.R., Bucureşti, 1964. 8 E . Poppel, S. Petrovan, Contract de cercetare ştiinţifică (Combinatul de C e l u l o z ă şi Hîrtie Drobeta Turnu-Severin), 1974. 9 Ε. Poppel, S. Petrovan, Das Papier, under press. 10 E. Poppel, S. Petrovan, Contract de cercetare ştiinţifică (Combinatul de C e l u l o z ă şi Hîrtie Drobeta Turnu-Severin), 1975. 11 Cr. Simionescu, E . Poppel, S. Petrovan, Paper presented at the International Meeting of the International Academy of Wood Science, Banska Bystrica, 1975. 12 13 14
E . Poppel, S. Petrovan, Cr. Simionescu, Chem. and Technol. 2, 4, 444 (1968).
Cellulose
E. Poppel, I . Bicu, Das Papier, 2 2 , 12, 882(1968). E . Poppel, I . Bicu, Das Papier, 23, 10 A, 672(1969)
15
E . Poppel, I . Bicu, Das Papier, 26, 4, 162 (1972).
2.SIMIONESCUFibrous Materials ajid Paper Products
71
16 I . Bicu, V. Popa, E. Poppel, Cr. Simionescu, Z e l l stoff und Papier, 2 1 , 1,8 (1972). 17 18
E. Poppel, I. Bicu, V. Dobronăuţeanu, Das Papier, 29, 3,93 (1975). E. Poppel, I . Bicu, Z. Ládo, Cellulose Chem. and Technol., 9, 4, 413 (1975).
19 20 21 22
I. Bicu, V. Popa, E . Poppel, C e l u l o z ă şi H î r t i e , 18, 10, 498 (1969). Ε. Poppel, Cr. Simionescu, Buletinul I.P. Iaşi, 8 (12), 1-2, 1977 (1962). I. Bicu, Doctorat thesis, I.P. Iaşi, 1972. E. Poppel, D. Ciobanu, Zellstoff u. Papier, 1975, 3, 68.
23 24 25 26
E. Poppel, D. Ciobanu, Zellstoff u. Papier, 1975, 5, 135. E. Poppel, D. Ciobanu, F. Andruchovici, Zellstoff u. Papier, 1975, 11, 323. E. Poppel, D. Ciobanu, Zellstoff u. Papier, under press. Cr. Simionescu, A. Liga, Patent R.S.R. 73064(1972)
27 28
N. Asandei, A. Liga, C. Stan, C. Moisă, Patent R.S.R. 59353 (1976). Cr. Simionescu, V. Rusan, A. Liga, V. Nuţă, D. Buhman, unpublished data.
29
D. Feldman, M. Ciubotaru, M. Ciugureanu, Rev. Roum. de Chimie, 1976 (under print) 30
A. Stoleriu, paper communicated at the first Microsymposium of macromolecular chemistry, I a ş i ,
November 14-15, 1975. 31
D. Buhman, Z. Ládo, V. Ungureanu, paper communicat ed at the 1st Microsymp.macromo.chem.Iaşi,14-15.XI. 1975.
