Introduction
Why SC PSF
Specifications of Recron SC PSF
Use & Benefits
Contact

Introduction
Short Cut Polyster Staple Fibre (SC PSF) is essentially a 1.5 denier, crimped, straight, 6mm speciality fibre. This has been developed by Reliance Industries Limited after extensive R&D efforts at Reliance Technology Centre.

As a reinforcement in paper pulps, it has been well established that the addition of 0.5% to 1.5% SC PSF significantly improves the Tear Factor, whereas the Burst Factor and Breaking Length shows slight improvement depending upon the pulp refining characteristics.

Why SC PSF
SC PSF is a tough synthetic fibre with a 6mm cut length, which helps in improving the Tear resistance of paper. The fibre addition allows greater refining possibilities and optimisation of Tensile and Burst Factors. Any loss of Tear Factor is effectively made up by SC PSF improving the three dimensional strength of paper. This is best explained by the following graphs.

There is greater possibility of optimising ash content in paper without adversely affecting machine runnability. This results in cost savings to paper mills. Higher strength index also makes it possible to optimise the use of costlier furnish by replacing certain components with cheaper furnish without any appreciable effect on the strength properties of paper or its machine runnability. As the Recron SC PSF has a melting point of 254 degree c, it offers no problem during drying of paper.

It is very much compatible with all kinds of paper chemicals,dyes and wetend additives that are used in stock preparation. Due to low moisture absorbency of this synthetic fibre, it offers higher wet-web strength to the paper thereby substantially reducing the wet end paper breaks.

Specifications of Recron SC PSF

Properties

Unit

Value

Denier

d

1.4-1.6

Tenacity

g/d

3.5-4.5

Elongation

%

>45.0

DHS

%

3.0-4.0

FOF

%

0.25-0.45

Cut length

MM

6+/-0.4

Moisture

%

0.5 to 1.0

Melting Range

Degree C

250-260

Dispersion

NA

Good

This fibre needs no processing prior to addition to pulp, as it does not require refining/beating, making the addition very easy.

Recron SC PSF
A New Age Fibre for the Paper Industry
Effect on drainage characteristics of pulp blend with Short Cut PSF
The SC PSF-pulp blend drains faster on the papermaking wire, as these fibres do not hold water, since their moisture regain is only about 0.4%. The stock freeness (degreeSR) some times changes by 2degree-3degree SR and may possibly affect the sheet fromation if the drainage is not controlled properly. A better sheet formation could be acheived by either refining the cellulose pulp to a higher degree SR level or by enhancing the machine speed, machine draw, etc. without affecting the GSM of paper.

Improvement in Wet-Strength
Due to lower moisture regain, excellent dimensional stability, better drainage characteristics and good wet strength of paper sheet increases. Longer fibre length of SC PSF increases Tear Resistance of Paper. All these factors influence the wet web strength of paper, resulting in lower wet end breaks and improved machine runnability.

Effect on dimensional stability
The dimensional stability of paper depends primarily on the extent of variation in moisture levels that paper may undergo during or after it is formed on the paper machine. The reinforecement of paper by polyster fibres helps in forming a sheet with better dimensional stability as these polyster fibres have a high melting point(254 degree C), they are comparatively more stable and do not have a tendency to shrink or deform during sheet drying. Higher dimesional stability in paper is desirable for all varieties of paper which are used for high speed printing i.e. Map Paper, Electrical Insulation Papers, etc.,

Effect on void volume of paper
The Reinforecement of polyster fibres in paper makes the paper more porous, increasing the porosity of paper. The polyster fibres, unlike cellulose fibres, being long (6mm) and with circular solid crosssection, form relatively more voids in the sheet and help in faster drainage on the forming wire of the paper mchine. The higher void volume allows higher retention of fillers in the voids thereby increasing ash content in paper.

Improvement in bulk
The bulk of paper is a function of thickness and basis weight. The reinforcement of polyster fibres, which are solid rod-like and tough, do not get compressed during the pressing/drying operations and result in a comparatively thicker mat. Therefore, the final sheet of paper with the same GSM shows higher thinckness and bulk. The improved bulk is especially important in all kinds of printing papers as the show-through effect in printing is reduced.

Significant improvement in tear
The Polyster fibres,when added to the cellulose pulp,improve the tear resistance of paper, essentially due to its long length(6mm) and great toughness . During the process of tearing of paper, the cellulose fibres often get cut; however, the synthetic fibres do not and thus hinder the propagation of tear, thereby increasing the tear strength.

Effect on breaking length and bursting strength
Synthetic to synthetic inter-fibre bonding is slightly weaker as SC PSF, has solid circular cross-section and therefore contact area between the fibres is less. Hence, the Breaking length and Burst Factor do not show significant improvement. However, this may be improved by adding crimped fibre in the furnish.

Effect on printability
The reinforcement of Short Cut PSF, in Writing & Printing papers helps improve the surface smoothness due to optimum use of ash resulting in better printing surface. The papers reinforced with synthetic fibres pass the Wax-Pick test, which qualifies the sheet of paper for print quality. The IGT printability test also gives positive results for such papers. Therefore, addition of these fibres is recommended for newsprint as well as all the other printing paper varieties.

Recycling of broke
The recommended addition of Short Cut PSF to pulps which are in the range of 0.5%-1.5% for most varieties of paper, the resulting broke recycling does not pose any problem. Moreover, the quantum of these fibres contributed by the broke in the total furnish is negligible.

Value to the paper Industry
The use of SC PSF would help the Indian Paper Industry on its recovery path by Partially alleviating the shortage of "good pulp" and reducing dependence on imports. This would also Partially check forest depletion.

Improved paper quality
The Plant scale trials conducted at various paper mills in the country have shown that addition of SC PSF to cellulose pulp improves strength properties of paper. It is well established in Writing & Printing Papers manufactured in wood-based, agro-residue-based and waste paper-based paper-mills. The plant trial results are summarised furnish :

Plant Trial Results

Particulars

Paper Grade

Furnish

% SC PSF added

Basis Weight,GSM

Burst Factor

Bulk,cc/g

Ash Content,%

Value-added technical Service:
The Reliance technical team consisting of experienced Paper Technologies provides full support on the suitability of the fibre to ensure the best possible results. The team also helps in identifying many more creative applications.
Packing
Recron SC PSF comes in the form of bales of 275-300 kg.These bales are wrapped with HDPE bale covers and are tightly strapped with MS wires as shown in the accompanying photograph.